I've only ever posted pictures via Flickr, Russ, but I'm guessing it's similar for other publicly accessible servers.
Post your picture to Flickr then alter the size to fit here - I can't remember what the size restrictions are but it tells you if it's too big, when you try to post it here. Right click on your photo to find its web address, copy it, click on the Img button above (here) and paste.
I'm sure that's as clear as mud, but hopefully it'll jog your memory as to how to do it.
And we'd love to see your summer house.