Get a free account at an online photo storage/sharing site, such as FlickR. Then, view the photos (on the flickR webpage) in another browser window. Right-click on the photo you want to attach, and select the command "Copy Image Location". Then, switch to the other browser window with your bikeforums message in it, click on the little, square, yellow, icon. A pop-up window will open, asking you for the URL of the image you want to share. Hit the Command-V keys on your keyboard which will paste the URL address of the picture from flickR. Then hit Enter, and, voila, there's your picture. Click on the Preview button at the bottom to see if you like it.

Nic pics from your ride, BTW.