[vishnumohandas]

TIL about progressive JPEGs, will check it out, thanks!

We currently render the thumbnail first (in most cases it's available locally) and then replace it with the original image once fetched from remote, while replicating the zoom and pan operations (if any) performed by the user. So it is "progressive" in some sense, but goes from something like 20% to 100% in one shot.

("20%" is a simplification, the actual value will depend on the resolution of the original image and that of the generated thumbnail, the latter is fixed)