Gallery vs profile images mouse use

I'm just wondering why mouse use is different between image galleries and the images in girls profiles?

When you've zoomed in on an image in a image gallery you have to click and hold the mouse button to move the image up and down. When doing the same thing on an image in a girls profile you can just move the mouse up and down and the image moves up and down.

This is no big deal, but I'm just wondering why there is this small inconsistency when the image galleries seem to be hosted on babepedia.