image-files = path mask + result ->
  - files path mask ( file-name -> - i file-name ( n -> attach result n ) )
;

i image-files = name @fp ->
  - fp name
  [ name->has-image-ext && file-size name > 0 ]
;

has-image-ext i -a = name ->
  [ name '.png', '.gif', '.jpg', '.jpeg' ]         
;