diff --git a/src/routes/_utils/decodeImage.js b/src/routes/_utils/decodeImage.js
index 0efbc12c..d4407e2d 100644
--- a/src/routes/_utils/decodeImage.js
+++ b/src/routes/_utils/decodeImage.js
@@ -1,5 +1,10 @@
+const IS_FIREFOX = process.browser && /Firefox/.test(navigator.userAgent)
+
 export function decodeImage (img) {
-  if (typeof img.decode === 'function') {
+  // Remove this UA sniff when the Firefox bug is fixed
+  // https://github.com/nolanlawson/pinafore/issues/1344#issuecomment-514312672
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=1565542
+  if (!IS_FIREFOX && typeof img.decode === 'function') {
     return img.decode()
   }