and the real simple part is to keep them at or under 800 pixels on the longest side. The reasons are very simple as well. Dial ups have problems with large posts and often won't even hang around to look while they load. That included me and a few others not so long ago.If we allow people to post larger or more images just because they have their own hosting or site, then that has to apply to all. That then means that the images we host here become more and larger and take up hosting space. We do like to be able to have that service for members, so therefor the rules are for everyone.
Rant over
and have a grasshopper slightly modified Danny.
A grasshopper with balls, three of them. Don't know how ya do it. 
