OOps.... Once you get to the manage attachments...... click browse and double click the picture you want to add from your computer files. (If the picture is too big, it won't attach... I have to shrink mine) Then click on upload and wait while it uploads the file. It will show when it is done. Then you close the box and you will be able to see the file you uploaded. Then you just select the whole thing to post.
Good luck.... We want to see your pictures.