(?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*\.(?:jpg|gif|png))(?:\?([^#]*))?(?:#(.*))?
That’s a (slightly modified) version of the official URI parsing regexp from RFC 2396. It allows for #fragments
and ?querystrings
to appear after the filename, which may or may not be what you want. It also matches any valid domain, including localhost
, which again might not be what you want, but it could be modified.
A more traditional regexp for this might look like the below.
^https?://(?:[a-z0-9\-]+\.)+[a-z]{2,6}(?:/[^/#?]+)+\.(?:jpg|gif|png)$ |-------- domain -----------|--- path ---|-- extension ---|
EDIT See my other comment, which although isn’t answering the question as completely as this one, I feel it’s probably a more useful in this case. However, I’m leaving this here for karma-whoring completeness reasons.