I'm going from memory here.....so this might be more of a guideline than instructions....You post them from your gallery. Go to the gallery photo that you want to share. Click on "edit" and verify that the "allow embedding" box is checked. You can only post to the forums if this box is checked. Click "save" and then look for the "share" button on the right. Click the share (or it might be "embed") icon. A box will pop up that allows you to share the photo. Click on the choice that is for "forums" (I think the second choice that appears). Choose your size, and then copy the code. Go to the thread that you want to post your photo in and paste the link.