CMS Image resizing issues with pop-ups
 

Hello
I've inserted a 800x450 gif inline on a cms article page. My pop-up window does not resize the image to the maximum image size. It shows the same size that is on the article. In my attachments manager, I have all image extensions set to max size width 800 and height 600.
Also, gifs seem to get cropped on the article page, and jpegs don't get cropped. The pop-ups show the uncropped version for the gifs, but still not at the full pop-up size.
This isn't the same issue as the 'display full article' problem as I do not have that ticked in my publishing options.
Is there any documentation on cms image sizing/pop-ups?
Thanks :)
Minty