Re: That's a per asset cache bust string
Both IGotOut and Donn Bly claim to have the same url, and it's also shared across articles
Yes, as it should be - as it's the exact same icon! Its "unique" URL ensures it's only fetched once by your browser, and reused if it's in its cache, as it should be. With that URL structure, and assuming you don't clear all caches when your browser closes, and assuming you have enough space in your browser's cache (and... yadda yadda yadda) you only "pay" the "download price" for that image once every 13months, as that's the validity of a "design picker" URL.
If we ever were to change the image served by that path part (sans SHA), and for some obscure reason we wanted to retain its path part as-is (which is silly... just create a new file!), we would have the option of "simply" sticking in a new SHA, and everyone would fetch the new image, and cache the new image for 13mo.
This isn't _that_ useful for static assets like furniture images, or site logo, or the like - as those very seldom change and often enough we can/do/will just use a new file name. This is, though, _very_ useful for us to be able to cache-bust the site JS and CSS at-will "just" by changing the SHA in the URL.
The reason we put the cache bust string on all those places is simply because this way we can be conservative in the expiration time given when the "real" /Design/... file is requested (7d) and can be lax (13mo expiration) when the URL path is, instead, "more unique".
Think of the /design_picker/SHA/PATH as a RewriteRule for /PATH, which adds a longer expiration time - that's pretty much exactly what it is; no more, and no less.
It's (also) a cache buster, and it's working exactly how it should be - for the things that need it as a cache buster; for those who need it for the higher expiration time, it's also performing as required.
Hope this helps! For anything more, though, webmaster@