Oversize images not scaled
 

When uploading images to albums if the image is smaller than the max size it uploads without problems but if it is even a little oversize the upload continues for maybe ten minutes the switches to a blank page with the picture(s) not uploaded.

I have other sites with older versions of vBulletin on the same server and with Photopost running. Photopost does not have a problem so I am guessing the problem is not with GD.

Can anyone suggest what to do?

Thanks