this works really well, but I found that (at least under mac os x) I had to change the following:

 # Download the image and save it to disk.
   my $req = HTTP::Request->new(GET => "http://$imgurl");
 
to 

 # Download the image and save it to disk.
   my $req = HTTP::Request->new(GET => $imgurl);
  
as the original version would just try to fetch "." and puke out. 

I don't know if that's due to what's on the mac, or no, but at least for me $imgurl already passes "http://link.to.image/image.jpg". 

so, just make that tiny change if you're running into problems fetching stuff. 

a very nifty app, very fun to max out your CPU fetching an ungodly number of images!