diff --git a/layouts/shortcodes/multithumb.html b/layouts/shortcodes/multithumb.html
index 237373b..0d19d05 100644
--- a/layouts/shortcodes/multithumb.html
+++ b/layouts/shortcodes/multithumb.html
@@ -2,7 +2,7 @@
 {{ range $param := .Params }}
   {{ $image :=  resources.GetMatch ($param) }}
   {{ $size := "x350" }}
-  {{ $options := printf "%s %s %s" $size "jpg q90" "Box"}}
+  {{ $options := printf "%s %s %s" $size "png q90" "Box"}}
   {{ $imagethumbnail := $image.Resize $options}}
   <a href="{{ $image.RelPermalink }}">
     <img class="thumbnail w6 pa1 mr1" src="{{ $imagethumbnail.RelPermalink }}" style="width: 95% !important;" />