How do I group resources by say MediaType?

support
1

It’s easy to group pages, e.g. .Pages.GroupBy "Dir" or .Pages.GroupBy "Section", but is it possible to do the same for .Resources? E.g. by MediaType so that I got one group for image/jpeg and another for image/png, or by .Dir, etc.

2 
{{$pngImages := where (.Resources.ByType "image") "MediaType.SubType" "png"}}
{{range $pngImages}}
...
{{end}}