We'll be working on userpics and static images during tonight's maintenance window. We're transitioning the hosting of these to Speedera, a content delivery network. This means after tonight these images will be served from caches all around the world. The use of a CDN for our static and media files enables us to focus our efforts on the continued improvement of performance on our html pages. We're confident you will notice an improvement in the performance of userpics, as well.
There will be no URL changes and this should be seamless to you, with the exception that userpics may be slow for the next few hours (and in to tomorrow) while the world-wide caches fill.
We've never worked with this company, so we'll all see how they do together. We have a one-month trial period to see how we like them :)
I will update here once we have finished our transition.