diff --git a/app/javascript/flavours/glitch/images/glitch-preview.jpg b/app/javascript/flavours/glitch/images/glitch-preview.jpg
deleted file mode 100644
index fc5c420435..0000000000
Binary files a/app/javascript/flavours/glitch/images/glitch-preview.jpg and /dev/null differ
diff --git a/app/javascript/flavours/glitch/images/glitch-preview.png b/app/javascript/flavours/glitch/images/glitch-preview.png
new file mode 100644
index 0000000000..af70d24fc0
Binary files /dev/null and b/app/javascript/flavours/glitch/images/glitch-preview.png differ
diff --git a/app/javascript/flavours/glitch/theme.yml b/app/javascript/flavours/glitch/theme.yml
index 49d71e085c..e6b748da77 100644
--- a/app/javascript/flavours/glitch/theme.yml
+++ b/app/javascript/flavours/glitch/theme.yml
@@ -33,7 +33,7 @@ inherit_locales: vanilla
 
 #  (OPTIONAL) A file to use as the preview screenshot for the flavour,
 #  or an array thereof. These are the full path from `app/javascript/`.
-screenshot: flavours/glitch/images/glitch-preview.jpg
+screenshot: flavours/glitch/images/glitch-preview.png
 
 #  (OPTIONAL) The directory which contains the pack files.
 #  Defaults to the theme directory (`app/javascript/themes/[theme]`),
diff --git a/app/javascript/flavours/vanilla/theme.yml b/app/javascript/flavours/vanilla/theme.yml
index b7678dc441..ecfb00729b 100644
--- a/app/javascript/flavours/vanilla/theme.yml
+++ b/app/javascript/flavours/vanilla/theme.yml
@@ -28,7 +28,7 @@ locales: ../../mastodon/locales
 
 #  (OPTIONAL) A file to use as the preview screenshot for the flavour,
 #  or an array thereof. These are the full path from `app/javascript/`.
-screenshot: images/screenshot.jpg
+screenshot: images/screenshot.png
 
 #  (OPTIONAL) The directory which contains the pack files.
 #  Defaults to this directory (`app/javascript/flavour/[flavour]`),
diff --git a/app/javascript/images/screenshot.jpg b/app/javascript/images/screenshot.jpg
deleted file mode 100644
index 45b270fbb0..0000000000
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diff --git a/app/javascript/images/screenshot.png b/app/javascript/images/screenshot.png
new file mode 100644
index 0000000000..e4401ba6df
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