Summary: public
The image loader was previously returning on the main thread, which could lead to poor performance due to various call sites doing further image processing (resizing, cropping, etc.) directly in the completion block.
This diff modifies the loader to return on a background thread (the same one used to load the image), and updates the call sites to dispatch to the explicit thread they need.
Reviewed By: javache
Differential Revision: D2549774
fb-gh-sync-id: fed73b7c163fdf67ff65bae72ab1986327e75815