timster - 11:48 pm on Feb 28, 2011 (gmt 0)
Just to be sure we are on the same page, I am assuming you want to match the full filename and also the file extension from an image tag that points to a specific directory on a specific domain. Also note, this solution will only match the first image tag found in the supplied string.
$filename = $matches; # Contents of the first backreference
$filetype = $matches; # Contents of the second backreference
Note the parentheses:
These identify “backreferences” which are returned by the matches array starting at index 1.