Hiya Met, welcome.
You can either attach them or just link them. I like to just link them from my photobucket account. That way I don't have to worry about the space I use up.
Upload them to a photo account then use the image tags and link.....
If you "quote" this post, you'll see "i40.photobucket.com/albums/e216/rabidbluesquirrel/tinystuck1.jpg" with the http and the IMG tags around it.