No problemo
If you wish to post an image in your reply, then host the image with photobucket or imageshack (either will do) and enclose them in the "[IMG] [/IMG]" tags. However, it's a real pain in the ass when people post images that stretch the forum, so don't post anything over 800x600. Smaller yet would be better, for our 56k friends
In cases where it's bigger, simply copying the URL into the post will make an auto-link to it in a different page, so it wont stretch the thread out.