I wonder if it might be because Wiki Commons addresses start http://commons
and not http://www
like most other addresses?
Hmmm ... I tried some images on Creative Commons that had filenames like "...xxx.jpg/...xxx.jpg" and got the same issue and thought that might be the reason, or that the size might be too big, but this one:
http://upload.wikimedia.org/wikipedia/c ... photos.jpg
is only 35K, has a normal filename, etc. and fails. Its not a WWW address, but nor is the image on my blog:
http://kgarden.files.wordpress.com/2012 ... 00x600.jpg
which works (well, for me at least!)
Dunno then, sorry, but its clearly useless
although I do think the concept has some merit - rather than just blindly choosing a compression and hoping that it is enough, but not stealing too much quality. Not valid for every image, every time, but for our websites we consider it extremely important that images are kept to a minimum size so that the page loads quickly for the users, and uses the minimum bandwidth.
I should have got my coat the first time!!