I use free prog imagoWEB when I want something to view all pictures in a file, it can be set to re-size everything to fit the window. Can also edit pictures with it. Still available I think from softcom.net/users/mikey719/visua_screenshot.html

I also use Ahaview if I want to see thumbnails as well - can line it up so thumbnails right, good sized version of the pic on the left. Excellent as well in that thumbs can be selected and moved/copied to other folders, renamed or sent to your default editing program. Not free, but there is a trial version available, and one of the best $20 software buys I've made. From aha-soft.com/products.htm - New version just out, which I haven't tried.

Final thought - when browsing I simply resize using the rescale button on Opera's address bar - do other browsers not do this?