That depends on what you mean by not handle. If it's storage, I never upload pictures to a forum. I upload them to an image host site, and just put a link on the forum. The pictures show up, but all that's stored on the forum are a few characters of code.Don't do that. the sight couldn't handle all the pictures.
If you mean not handle by being slow to load, such as on dial up, yup, pictures take time to load no matter where they are stored.
I really prefer the host site as I can upload it once, then post it to several forums.