I shoot for 72 DPI, ~600X400 pixels max. Depending on the image this rarely results in a file larger than 100Kb, pretty small as images go, but usually large enough to fill most screens without scrolling, and all the resolution needed for web presentation (new hi-res "retina" displays excluded). An image of around 100Kb or less will come up immediately with DSL, and 4 to 5 seconds on dial–ups (). See Netproofing.
That said, I no longer post images on other's servers. I link to the URL's on my own site, so as not to overload hosts. That would require you use your own site, which you could, and probably should, do remotely (i.e., the cloud) anyhow, often for free (see WebMarketing).
Last edited by ROL; 02-22-2012 at 03:01 PM. Click to view previous post history.