diff --git a/public/scripts/extensions/expressions/index.js b/public/scripts/extensions/expressions/index.js
index e31807893..21e0d6df2 100644
--- a/public/scripts/extensions/expressions/index.js
+++ b/public/scripts/extensions/expressions/index.js
@@ -1283,8 +1283,6 @@ async function drawSpritesList(character, labels, sprites) {
  * @returns {Promise<string>} Rendered list item template
  */
 async function getListItem(item, imageSrc, textClass, isCustom) {
-    const isFirefox = navigator.userAgent.toLowerCase().indexOf('firefox') > -1;
-    imageSrc = isFirefox ? `${imageSrc}?t=${Date.now()}` : imageSrc;
     return renderExtensionTemplateAsync(MODULE_NAME, 'list-item', { item, imageSrc, textClass, isCustom });
 }
 
diff --git a/src/endpoints/sprites.js b/src/endpoints/sprites.js
index 733b12478..6a2e5e6b9 100644
--- a/src/endpoints/sprites.js
+++ b/src/endpoints/sprites.js
@@ -124,9 +124,10 @@ router.get('/get', jsonParser, function (request, response) {
                 })
                 .map((file) => {
                     const pathToSprite = path.join(spritesPath, file);
+                    const mtime = fs.statSync(pathToSprite).mtime?.toISOString().replace(/[^0-9]/g, '').slice(0, 14);
                     return {
                         label: path.parse(pathToSprite).name.toLowerCase(),
-                        path: `/characters/${name}/${file}`,
+                        path: `/characters/${name}/${file}` + (mtime ? `?t=${mtime}` : ''),
                     };
                 });
         }