feat: add per-gallery thumbnail scale setting (#172) (#251)

Add a thumbnailScale field (xs/sm/md/lg/xl) to gallery layout settings
that adjusts column counts for Grid, Masonry (columns mode), and Mosaic
layouts. Each scale maps to a column offset applied on top of the
layout's base columns, letting photographers control photo density.

- Add thumbnailScale to GalleryLayoutSettings type
- Apply scale offset in Grid, Masonry, and Mosaic layout components
- Add thumbnail scale dropdown to admin theme customizer
- Conditionally show dropdown only for applicable layouts
- Safelist dynamic grid-cols classes in Tailwind config
- Add i18n keys for EN, DE, PT, RU locales

Co-authored-by: Paul Nothaft <[email protected]>

frontend/src/components/admin/ThemeCustomizerEnhanced.tsx

@@ -312,52 +312,73 @@ export const ThemeCustomizerEnhanced: React.FC<ThemeCustomizerEnhancedProps> = (
 
               {/* Grid specific */}
               {localTheme.galleryLayout === 'grid' && (
-                <div>
-                  <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
-                    {t('branding.columns')}
-                  </label>
-                  <div className="grid grid-cols-3 gap-4">
-                    <div>
-                      <label className="text-xs text-neutral-600 dark:text-neutral-400">{t('branding.mobile')}</label>
-                      <Input
-                        type="number"
-                        min="1"
-                        max="4"
-                        value={localTheme.gallerySettings?.gridColumns?.mobile || 2}
-                        onChange={(e) => updateGallerySettings('gridColumns', {
-                          ...localTheme.gallerySettings?.gridColumns,
-                          mobile: parseInt(e.target.value)
-                        })}
-                      />
-                    </div>
-                    <div>
-                      <label className="text-xs text-neutral-600 dark:text-neutral-400">{t('branding.tablet')}</label>
-                      <Input
-                        type="number"
-                        min="2"
-                        max="6"
-                        value={localTheme.gallerySettings?.gridColumns?.tablet || 3}
-                        onChange={(e) => updateGallerySettings('gridColumns', {
-                          ...localTheme.gallerySettings?.gridColumns,
-                          tablet: parseInt(e.target.value)
-                        })}
-                      />
-                    </div>
-                    <div>
-                      <label className="text-xs text-neutral-600 dark:text-neutral-400">{t('branding.desktop')}</label>
-                      <Input
-                        type="number"
-                        min="3"
-                        max="8"
-                        value={localTheme.gallerySettings?.gridColumns?.desktop || 4}
-                        onChange={(e) => updateGallerySettings('gridColumns', {
-                          ...localTheme.gallerySettings?.gridColumns,
-                          desktop: parseInt(e.target.value)
-                        })}
-                      />
+                <>
+                  <div>
+                    <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
+                      {t('branding.columns')}
+                    </label>
+                    <div className="grid grid-cols-3 gap-4">
+                      <div>
+                        <label className="text-xs text-neutral-600 dark:text-neutral-400">{t('branding.mobile')}</label>
+                        <Input
+                          type="number"
+                          min="1"
+                          max="4"
+                          value={localTheme.gallerySettings?.gridColumns?.mobile || 2}
+                          onChange={(e) => updateGallerySettings('gridColumns', {
+                            ...localTheme.gallerySettings?.gridColumns,
+                            mobile: parseInt(e.target.value)
+                          })}
+                        />
+                      </div>
+                      <div>
+                        <label className="text-xs text-neutral-600 dark:text-neutral-400">{t('branding.tablet')}</label>
+                        <Input
+                          type="number"
+                          min="2"
+                          max="6"
+                          value={localTheme.gallerySettings?.gridColumns?.tablet || 3}
+                          onChange={(e) => updateGallerySettings('gridColumns', {
+                            ...localTheme.gallerySettings?.gridColumns,
+                            tablet: parseInt(e.target.value)
+                          })}
+                        />
+                      </div>
+                      <div>
+                        <label className="text-xs text-neutral-600 dark:text-neutral-400">{t('branding.desktop')}</label>
+                        <Input
+                          type="number"
+                          min="3"
+                          max="8"
+                          value={localTheme.gallerySettings?.gridColumns?.desktop || 4}
+                          onChange={(e) => updateGallerySettings('gridColumns', {
+                            ...localTheme.gallerySettings?.gridColumns,
+                            desktop: parseInt(e.target.value)
+                          })}
+                        />
+                      </div>
                     </div>
                   </div>
-                </div>
+                  <div>
+                    <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
+                      {t('branding.thumbnailScale', 'Thumbnail Scale')}
+                    </label>
+                    <select
+                      value={localTheme.gallerySettings?.thumbnailScale || 'md'}
+                      onChange={(e) => updateGallerySettings('thumbnailScale', e.target.value)}
+                      className="w-full px-3 py-2 border border-neutral-300 dark:border-neutral-600 rounded-lg bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100"
+                    >
+                      <option value="xs">{t('branding.thumbnailScaleOptions.xs', 'XS — Most photos')}</option>
+                      <option value="sm">{t('branding.thumbnailScaleOptions.sm', 'SM — More photos')}</option>
+                      <option value="md">{t('branding.thumbnailScaleOptions.md', 'MD — Default')}</option>
+                      <option value="lg">{t('branding.thumbnailScaleOptions.lg', 'LG — Larger photos')}</option>
+                      <option value="xl">{t('branding.thumbnailScaleOptions.xl', 'XL — Largest photos')}</option>
+                    </select>
+                    <p className="text-xs text-neutral-500 dark:text-neutral-400 mt-1">
+                      {t('branding.thumbnailScaleHint', 'Adjusts column count relative to the base grid columns')}
+                    </p>
+                  </div>
+                </>
               )}
 
               {/* Carousel specific */}
@@ -437,6 +458,29 @@ export const ThemeCustomizerEnhanced: React.FC<ThemeCustomizerEnhancedProps> = (
                     </p>
                   </div>
 
+                  {/* Thumbnail scale - only for columns mode */}
+                  {(!localTheme.gallerySettings?.masonryMode || localTheme.gallerySettings?.masonryMode === 'columns') && (
+                    <div>
+                      <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
+                        {t('branding.thumbnailScale', 'Thumbnail Scale')}
+                      </label>
+                      <select
+                        value={localTheme.gallerySettings?.thumbnailScale || 'md'}
+                        onChange={(e) => updateGallerySettings('thumbnailScale', e.target.value)}
+                        className="w-full px-3 py-2 border border-neutral-300 dark:border-neutral-600 rounded-lg bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100"
+                      >
+                        <option value="xs">{t('branding.thumbnailScaleOptions.xs', 'XS — Most photos')}</option>
+                        <option value="sm">{t('branding.thumbnailScaleOptions.sm', 'SM — More photos')}</option>
+                        <option value="md">{t('branding.thumbnailScaleOptions.md', 'MD — Default')}</option>
+                        <option value="lg">{t('branding.thumbnailScaleOptions.lg', 'LG — Larger photos')}</option>
+                        <option value="xl">{t('branding.thumbnailScaleOptions.xl', 'XL — Largest photos')}</option>
+                      </select>
+                      <p className="text-xs text-neutral-500 dark:text-neutral-400 mt-1">
+                        {t('branding.thumbnailScaleHint', 'Adjusts column count relative to the base grid columns')}
+                      </p>
+                    </div>
+                  )}
+
                   {/* Row-specific settings - show for all row-based modes */}
                   {['rows', 'flickr', 'justified'].includes(localTheme.gallerySettings?.masonryMode || '') && (
                     <>
@@ -476,6 +520,29 @@ export const ThemeCustomizerEnhanced: React.FC<ThemeCustomizerEnhancedProps> = (
                   )}
                 </>
               )}
+
+              {/* Mosaic specific */}
+              {localTheme.galleryLayout === 'mosaic' && (
+                <div>
+                  <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
+                    {t('branding.thumbnailScale', 'Thumbnail Scale')}
+                  </label>
+                  <select
+                    value={localTheme.gallerySettings?.thumbnailScale || 'md'}
+                    onChange={(e) => updateGallerySettings('thumbnailScale', e.target.value)}
+                    className="w-full px-3 py-2 border border-neutral-300 dark:border-neutral-600 rounded-lg bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100"
+                  >
+                    <option value="xs">{t('branding.thumbnailScaleOptions.xs', 'XS — Most photos')}</option>
+                    <option value="sm">{t('branding.thumbnailScaleOptions.sm', 'SM — More photos')}</option>
+                    <option value="md">{t('branding.thumbnailScaleOptions.md', 'MD — Default')}</option>
+                    <option value="lg">{t('branding.thumbnailScaleOptions.lg', 'LG — Larger photos')}</option>
+                    <option value="xl">{t('branding.thumbnailScaleOptions.xl', 'XL — Largest photos')}</option>
+                  </select>
+                  <p className="text-xs text-neutral-500 dark:text-neutral-400 mt-1">
+                    {t('branding.thumbnailScaleHint', 'Adjusts column count relative to the base grid columns')}
+                  </p>
+                </div>
+              )}
             </div>
           )}
         </Card>

frontend/src/components/gallery/layouts/GridGalleryLayout.tsx

@@ -374,6 +374,10 @@ export const GridGalleryLayout: React.FC<BaseGalleryLayoutProps> = ({
   const columns = gallerySettings.gridColumns || { mobile: 2, tablet: 3, desktop: 4 };
   const spacing = gallerySettings.spacing || 'normal';
   const animation = gallerySettings.photoAnimation || 'fade';
+  const scale = gallerySettings.thumbnailScale || 'md';
+
+  const scaleOffsets: Record<string, number> = { xs: 3, sm: 1, md: 0, lg: -1, xl: -2 };
+  const applyScale = (cols: number) => Math.max(1, cols + (scaleOffsets[scale] ?? 0));
 
   const [showIdentityModal, setShowIdentityModal] = React.useState(false);
   const [pendingAction, setPendingAction] = React.useState<null | { type: 'like'; photoId: number }>(null);
@@ -381,12 +385,12 @@ export const GridGalleryLayout: React.FC<BaseGalleryLayoutProps> = ({
   const [savedIdentity, setSavedIdentity] = React.useState<{ name: string; email: string } | null>(null);
 
   const spacingClass = spacing === 'tight' ? 'gap-2' : spacing === 'relaxed' ? 'gap-6' : 'gap-4';
-  
+
   const gridClass = `photo-grid grid ${spacingClass}
-    grid-cols-${columns.mobile}
-    sm:grid-cols-${columns.tablet}
-    lg:grid-cols-${columns.desktop}
-    xl:grid-cols-${columns.desktop + 1}`;
+    grid-cols-${applyScale(columns.mobile)}
+    sm:grid-cols-${applyScale(columns.tablet)}
+    lg:grid-cols-${applyScale(columns.desktop)}
+    xl:grid-cols-${applyScale(columns.desktop + 1)}`;
 
   return (
     <div className={gridClass}>

frontend/src/components/gallery/layouts/MasonryGalleryLayout.tsx

@@ -241,6 +241,13 @@ export const MasonryGalleryLayout: React.FC<BaseGalleryLayoutProps> = ({
   const mode = gallerySettings.masonryMode || 'columns';
   const targetRowHeight = gallerySettings.masonryRowHeight || 250;
   const lastRowBehavior = gallerySettings.masonryLastRowBehavior || 'left';
+  const scale = gallerySettings.thumbnailScale || 'md';
+
+  const scaleOffsets: Record<string, number> = { xs: 3, sm: 1, md: 0, lg: -1, xl: -2 };
+  const applyScale = (cols: number) => Math.max(1, cols + (scaleOffsets[scale] ?? 0));
+
+  // Apply scale to columns only in columns mode
+  const scaledColumns = mode === 'columns' ? applyScale(columns) : columns;
 
 
   // Calculate number of columns based on container width (for columns mode)
@@ -339,20 +346,20 @@ export const MasonryGalleryLayout: React.FC<BaseGalleryLayoutProps> = ({
   // This creates a more balanced masonry layout instead of round-robin
   const photoColumns: Photo[][] = useMemo(() => {
     if (mode !== 'columns' || photos.length === 0) {
-      return Array.from({ length: columns }, () => []);
+      return Array.from({ length: scaledColumns }, () => []);
     }
 
-    const cols: Photo[][] = Array.from({ length: columns }, () => []);
-    const colHeights: number[] = Array(columns).fill(0);
+    const cols: Photo[][] = Array.from({ length: scaledColumns }, () => []);
+    const colHeights: number[] = Array(scaledColumns).fill(0);
 
     // Calculate approximate column width for height estimation
-    const approxColWidth = containerWidth > 0 ? (containerWidth - (columns - 1) * gutter) / columns : 300;
+    const approxColWidth = containerWidth > 0 ? (containerWidth - (scaledColumns - 1) * gutter) / scaledColumns : 300;
 
     photos.forEach((photo) => {
       // Find the shortest column
       let shortestCol = 0;
       let minHeight = colHeights[0];
-      for (let i = 1; i < columns; i++) {
+      for (let i = 1; i < scaledColumns; i++) {
         if (colHeights[i] < minHeight) {
           minHeight = colHeights[i];
           shortestCol = i;
@@ -373,15 +380,15 @@ export const MasonryGalleryLayout: React.FC<BaseGalleryLayoutProps> = ({
     });
 
     return cols;
-  }, [mode, photos, columns, containerWidth, gutter]);
+  }, [mode, photos, scaledColumns, containerWidth, gutter]);
 
   // Calculate approximate column width for aspect ratio calculations
   const columnWidth = useMemo(() => {
-    if (containerWidth <= 0 || columns <= 0) return 300;
+    if (containerWidth <= 0 || scaledColumns <= 0) return 300;
     // Account for gaps between columns
-    const totalGaps = (columns - 1) * gutter;
-    return (containerWidth - totalGaps) / columns;
-  }, [containerWidth, columns, gutter]);
+    const totalGaps = (scaledColumns - 1) * gutter;
+    return (containerWidth - totalGaps) / scaledColumns;
+  }, [containerWidth, scaledColumns, gutter]);
 
   // ROWS MODE - Google Photos style justified layout
   if (mode === 'rows') {

frontend/src/components/gallery/layouts/MosaicGalleryLayout.tsx

@@ -1,5 +1,6 @@
 import React from 'react';
 import { Download, Maximize2, Check, Heart, MessageSquare } from 'lucide-react';
+import { useTheme } from '../../../contexts/ThemeContext';
 import { AuthenticatedImage } from '../../common';
 import { FeedbackIdentityModal } from '../../gallery/FeedbackIdentityModal';
 import { feedbackService } from '../../../services/feedback.service';
@@ -210,23 +211,33 @@ export const MosaicGalleryLayout: React.FC<BaseGalleryLayoutProps> = ({
   feedbackEnabled = false,
   feedbackOptions
 }) => {
+  const { theme } = useTheme();
+  const scale = theme.gallerySettings?.thumbnailScale || 'md';
+  const scaleOffsets: Record<string, number> = { xs: 3, sm: 1, md: 0, lg: -1, xl: -2 };
+  const applyScale = (cols: number, min = 1) => Math.max(min, cols + (scaleOffsets[scale] ?? 0));
+
+  const desktop = applyScale(4);
+  const xlDown = applyScale(3);
+  const lgDown = applyScale(2);
+  const mobile = Math.min(applyScale(1), 2); // Cap mobile at 2
+
   return (
     <div
       className="photo-grid w-full"
       style={{
-        columnCount: 4,
+        columnCount: desktop,
         columnGap: '8px',
       }}
     >
       <style>{`
         @media (max-width: 1280px) {
-          .photo-grid { column-count: 3 !important; }
+          .photo-grid { column-count: ${xlDown} !important; }
         }
         @media (max-width: 1024px) {
-          .photo-grid { column-count: 2 !important; }
+          .photo-grid { column-count: ${lgDown} !important; }
         }
         @media (max-width: 640px) {
-          .photo-grid { column-count: 1 !important; }
+          .photo-grid { column-count: ${mobile} !important; }
         }
       `}</style>
       {photos.map((photo, index) => (

frontend/src/i18n/locales/de.json

@@ -1437,6 +1437,15 @@
       "center": "Zentriert",
       "justify": "Blocksatz (gestreckt)"
     },
+    "thumbnailScale": "Vorschau-Skalierung",
+    "thumbnailScaleOptions": {
+      "xs": "XS — Meiste Fotos",
+      "sm": "SM — Mehr Fotos",
+      "md": "MD — Standard",
+      "lg": "LG — Größere Fotos",
+      "xl": "XL — Größte Fotos"
+    },
+    "thumbnailScaleHint": "Passt die Spaltenanzahl relativ zu den Basis-Rasterspalten an",
     "showHeroSection": "Hero-Bereich anzeigen",
     "showHeroSectionHint": "Zeigt ein hervorgehobenes Titelbild über der Galerie an",
     "heroHeight": "Hero-Bereich Höhe",

frontend/src/i18n/locales/en.json

@@ -1152,6 +1152,15 @@
       "center": "Centered",
       "justify": "Justified (stretch)"
     },
+    "thumbnailScale": "Thumbnail Scale",
+    "thumbnailScaleOptions": {
+      "xs": "XS — Most photos",
+      "sm": "SM — More photos",
+      "md": "MD — Default",
+      "lg": "LG — Larger photos",
+      "xl": "XL — Largest photos"
+    },
+    "thumbnailScaleHint": "Adjusts column count relative to the base grid columns",
     "showHeroSection": "Show Hero Section",
     "showHeroSectionHint": "Display a featured hero image above the justified gallery",
     "heroHeight": "Hero Section Height",

frontend/src/i18n/locales/pt.json

@@ -1130,6 +1130,15 @@
       "center": "Centralizado",
       "justify": "Justified (esticado)"
     },
+    "thumbnailScale": "Escala de Miniaturas",
+    "thumbnailScaleOptions": {
+      "xs": "XS — Mais fotos",
+      "sm": "SM — Muitas fotos",
+      "md": "MD — Padrão",
+      "lg": "LG — Fotos maiores",
+      "xl": "XL — Fotos grandes"
+    },
+    "thumbnailScaleHint": "Ajusta a contagem de colunas em relação às colunas base da grade",
     "showHeroSection": "Mostrar Seção Hero",
     "showHeroSectionHint": "Exibir uma imagem hero em destaque acima da galeria justified",
     "heroHeight": "Altura da Seção Hero",

frontend/src/i18n/locales/ru.json

@@ -1130,6 +1130,15 @@
       "center": "По центру",
       "justify": "Justified (растянуть)"
     },
+    "thumbnailScale": "Масштаб миниатюр",
+    "thumbnailScaleOptions": {
+      "xs": "XS — Больше всего фото",
+      "sm": "SM — Больше фото",
+      "md": "MD — По умолчанию",
+      "lg": "LG — Крупнее фото",
+      "xl": "XL — Самые крупные фото"
+    },
+    "thumbnailScaleHint": "Изменяет количество колонок относительно базовых колонок сетки",
     "showHeroSection": "Показывать секцию баннера",
     "showHeroSectionHint": "Отображать главное фото баннера над justified-галереей",
     "heroHeight": "Высота секции баннера",

frontend/src/types/theme.types.ts

@@ -47,6 +47,9 @@ export interface GalleryLayoutSettings {
   
   // Mosaic specific
   mosaicPattern?: 'random' | 'structured' | 'alternating';
+
+  // Thumbnail scale (applies to Grid, Masonry columns, Mosaic)
+  thumbnailScale?: 'xs' | 'sm' | 'md' | 'lg' | 'xl';
 }
 
 export interface ThemeConfig {

frontend/tailwind.config.js

@@ -84,6 +84,13 @@ export default {
       },
     },
   },
+  safelist: [
+    // Dynamic grid-cols classes used by thumbnail scale offsets
+    ...Array.from({ length: 12 }, (_, i) => `grid-cols-${i + 1}`),
+    ...Array.from({ length: 12 }, (_, i) => `sm:grid-cols-${i + 1}`),
+    ...Array.from({ length: 12 }, (_, i) => `lg:grid-cols-${i + 1}`),
+    ...Array.from({ length: 12 }, (_, i) => `xl:grid-cols-${i + 1}`),
+  ],
   plugins: [],
 }