When you click reply a big white box pops up, that is where you type your reply into.
Just below that there are the words " Download ImageShack Toolbar! ".
Just below that is a small white box & the word "Browse".
Click the word browse & your files will open.
Select a photo & you will be redirected to imageshack.
You will be given a code to copy from imageshack.
Come back to the forum & post that code into your reply message & hit submit.
NOTE: Image shack will give you several codes, some work on some sitesm some work on others. I use the second code given for this forum.