You are over your image quotaIf you see this message while trying to upload a new logo or icons to your forum, it means as it says, you have to many images all ready.
1.Delete any images not being used, like old logos, old icons. (if you are using a template that uses say English_big and French_big get rid of the ones you will not be using) also a lot of templates have .psd files that are not used.
Please remember to make a backup of your template first before you do any editing.
2. Check the size of your new logo does it really have to be that big ??
Biggest mistake many make is to have a logo the size of the QE2 this does not only look bad but forces everyone to scroll half way down the page just to find your forum.