(cond ((string-match ".*\\.jpe?g\\'" img) 'jpeg)
((string-match ".*\\.xpm\\'" img) 'xpm)
((string-match ".*\\.xbm\\'" img) 'xbm)
+ ((string-match ".*\\.pbm\\'" img) 'pbm)
((string-match ".*\\.gif\\'" img) 'gif)
((string-match ".*\\.bmp\\'" img) 'bmp)
((string-match ".*\\.png\\'" img) 'png)