Use static height if gallery has single image

src/components/gallery/gallery.js

@@ -34,7 +34,9 @@ const Gallery = {
       return rows
     },
     rowHeight () {
-      return itemsPerRow => ({ 'height': `${(this.width / (itemsPerRow + 0.6))}px` })
+      return itemsPerRow => ({
+        'height': this.attachments.length === 1 ? '260px' : `${(this.width / (itemsPerRow + 0.6))}px`
+      })
     },
     useContainFit () {
       return this.$store.state.config.useContainFit

src/components/gallery/gallery.vue

@@ -1,6 +1,11 @@
 <template>
   <div ref="galleryContainer" style="width: 100%;">
-    <div class="gallery-row" v-for="row in rows" :style="rowHeight(row.length)" :class="{ 'contain-fit': useContainFit, 'cover-fit': !useContainFit }">
+    <div
+      v-for="(row, row_num) in rows"
+      :key="row_num"
+      :style="rowHeight(row.length)"
+      :class="{ 'gallery-row': true, 'contain-fit': useContainFit, 'cover-fit': !useContainFit }"
+    >
       <attachment
         v-for="attachment in row"
         :setMedia="setMedia"