I noticed a small problem with the current setup. If you update your gaslog the image will be updated, but most of us have cache on our browsers (for quicker page rendering) and the image will stay the same when we view it.
I have a solution but it will require everyone to change their signatures (again). I'll see if I have time tomorrow to get it working. I'll also set up an easy page for explaining how to post your gaslog image on other websites.