Also an iMac user using iPhoto . I use photobucket to upload my photos and share them. It was not hard to set up an account and I find it works as well with my iMac as any site worked with my old pc. I set the upload options to upload images to the 800x600 size which makes them usable in the photo contest and also seems to be a reasonable size for sharing on the boards as well. (You need to make sure you copy and paste the link for your image into the post it will automatically display as an image).
-MR.TK