diff --git a/src/views/mastoapi.nim b/src/views/mastoapi.nim
index ff33a4e..e489f00 100644
--- a/src/views/mastoapi.nim
+++ b/src/views/mastoapi.nim
@@ -42,10 +42,13 @@ proc getActivityStream*(tweet: Tweet, cfg: Config, prefs: Prefs): JsonNode =
       let
         image = getUrlPrefix(cfg) & getPicUrl(url)
         splitUrl = url.split('.')
+      var filetype = splitUrl[^1]
+      if filetype == "jpg":
+        filetype = "jpeg"
 
       var mediaObj = newJObject()
       mediaObj["type"] = %"Document"
-      mediaObj["mediaType"] = %("image/" & splitUrl[^1])
+      mediaObj["mediaType"] = %("image/" & filetype)
       mediaObj["url"] = %image
       mediaObj["name"] = newJNull() # FIXME a11y