I am now ready to switch the uploaded image serving over to plain old url's instead of via scripts. This will have a number of effects, most of which I hope will be invisible. This is a fairly major change in architecture, and is an effort to speed up the server. It is also going to contribute towards images being served at the right size even before they have loaded. For the moment, only image uploads will know their size in advance, but I have a plan to learn external image sizes too. This way the bottom of a page will not jump every time an image loads.
Some of the files already uploaded do not yet have the right file extensions, so you may see a few images not display properly for a little while. It's only about 12,000 out of over 200,000, and I don't know what their chronological distribution is.
Thanks for being patient. It's for your own good! ;-)