Compression can play a big part in the size of the photo. I try to keep ALL photos on my website at the recommended 50kb or less by using a combination of compression, resolution, and size.
Can you tell the difference between these 2 photos?
The first one is 82KB and the second one is 53kb. The second one will load quicker on slow connections. Sure, there may be a slight difference between the 2 but it is hardly noticed by most people and the guys with slower connections are less likely to leave before the photo is loaded. IMO, 100-200k is way larger than is ever needed on a web page.