The problem we see is that some members are buying much larger monitors. A 800 x 600 pixel upload should
be fine for a majority of users up to a 19 inch, maybe 20 inch monitor. Still you see a lot of 1024 x 768 uploads, due to it being the default. Still I try to get members to follow the max 800 pixel setting. Some do, some don't.
Basically your upload size should be one size smaller that your setting for your screen resolution on your monitor to avoid scrolling to read the text and see all the photo.