Before I post a photo here at the forum I go to "My Pictures" and right click on the chosen photo. One of the options that shows up is "resize pictures". I choose "small" which knocks the size way down. Then I choose "Additional options" in the "post reply" window, and browse till I find my chosen reduced size photo, and use "more attachments" to add more than one photo.
You could also go to the Gallery and make an account, I think theres 5mb to use there.