Taran is quite correct in what he says. this is the sequence for reducing file size of individual images in Photoshop 7.
With the photo open go to "Image"-"Image Size" selct approx 600 pixels, with "Constrain Proportions" selected the other dimension will adjust accordingly. Click on OK. Now select "Save As", type in your file name and in the box below select "Jpeg", click "Save". Another box will open entitled "Jpeg Options", in ths box is a slider, moving this to the left will reduce the file size.
At the bottom of the box you are able to see the actual size in in Kbs, along with the time it will take to upload to the 'net at any given. speed from 14.4 kbps to 2 MBs