Here's a GreaseMonkey script that adds this to the whole site automatically (!). It adds an icon next to each image link in the Atlas which submits the creation form to the Seadragon site, then embeds the result after the table for the current game. My Javascript is pretty awful
and I had to do some nasty hacks to make it work, but it does work, in the latest Firefox and latest GreaseMonkey.
Remove the .txt extension and drop it on Firefox to install.
[Edit: bugfix]
[Edit 2: improvements to the script, moved it to an attachment]
[Edit 3: added the subdomainless URL mask]