in reply to matching and backreferencing filenames

 ...And 
# what about camel case extensions? This long list seems 
# really innefficent. 

  (jpg|JPG|gif|GIF|wmv|WMV|mpg|MPG|avi|AVI)$/

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You can do case insensitive matching with the 'i' modifier after the final matching delimiter.

(jpg|gif|wmv|mpg|avi)$/i

In Section Seekers of Perl Wisdom