Eric, what I do is take my raw digital camera pictures and reduce them down to 500 X 375, which fit on a web page nicely. I use Paint Shop Pro 3.11, an old version, because it is so easy to use. THEN after I reduce the physical size, I user anothe program called "JPEG Optimizer". This program reduces the file size down to just about anything I want. The more you reduce the file size, the more the image quality degrades.
The picture below, was originally 415 KB, after it was reduced to 500 X 375, it's current size, it was 258 KB, now after running through Optimizer, it is only 31.7 KB.
You should be able to find the program at download.com.