To follow up on this... (1) To recap, I have a dozen of thumbnails of sizes ranging from 5kb to 15kb on one page (a gallery type of things). Observed occasional slow rendering of the page, on local server.
(2) I think this slowness has to do with rocket server. After trying on another server with Apache. This slowness disappeared. (3) That said, there's still an observed slow rendering as a result of web2py streaming images. Massimo claimed that there should be NO overhead. To my eyes, the overhead in streaming these small images are noticeable. I think Massimo might have underestimated the sensitivity of the eyes. The download is fast, but not fast enough for my eyes to still see flickering. And this can be quite *annoying*. (4) THE FIX: is the *fast_download* slice by Mariano Reingart!!! This does the trick. A comment to Mariano: you might want to add "import os, time" to the code. People might neglect to do this (as I did initially); without these imports, it of course doesn't work, without telling you why.
