Q:

Assets 2.0: Why do public templates stall while Assets is working in the admin panel?

I just updated a large EE 2.5.2 install to Assets 2.0 and updated indexes. Everything went smoothly, and I've noticed a strange new behavior: thumbnail generation (any size) in the admin panel will temporarily block the website from loading Assets images.
To reproduce:

Choose a large (100+ item) Assets folder to browse in the admin panel. Any view/thumbnail size will have the same effect.
While the thumbnails are loading, navigate to a page on the public website that uses Assets tags in its template.

The result: the page in #2 will stall until all thumbnails in #1 have finished loading. Immediately after finishing, the public page will load.
This is on a MediaTemple DV4 server with 2048MB RAM and plenty of resources, and several httpd instances. Could the mysql process be the bottleneck? What else might cause this to happen?
Edit: This appears to be limited to the same session. I originally tried this with Chrome 24 (Mac), running both #1 and #2 in different tabs. When I instead tried #2 in Firefox, there was no blocking and everything loaded as expected. Now I'm not sure if I've got a problem worth solving or a minor annoyance to live with. 

A:

this is because on the first request to a folder, Assets will create thumbnails appropriate for your screen (retina or not).
For 100+ files, that's 100+ requests that aren't instant and browsers limit simultaneous requests to the same server, so it's browser hitting the limit because of the initial processing required.
After this, though, the images will be created and stored and you shouldn't experience it for the same folder again. Even more - if you use the same browser, these images will be cached and won't make any requests at all.
Hope this clears things up for you!

