The easy way:
First be sure your photos are on your hard drive and saved under 500x500 pixels...most of the time you'll need to reduce them down from their origional size.
Second type in a threasd like i'm doing now.
third...after typing your response scroll down until you see a box marked "manage attachments"
Fourth...open the manage attachments option and browse to locate the photo you want to attach on your hard drive....upload it and then submit your thread.
the photo should appear.