Cliff, I noticed the graphic engines in different browers or even websites can have different rendering of the same jpg image. It's weird. When I hot linked these 3 images through RFF, they look pretty much the same, but when I open them individually in different tabs, the difference is more pronounced.
anyway here is the difference I see on my 23" samsung monitor.
image 1: very smooth rendering of a dusk scene.
image 2: noticably more detail in cloud highlights (upper left) and in the shadows (inside the dumpster). a slightly increased contrast/saturation throughout the image.
image 3: noticably more detail in cloud highlights (upper left) and in the shadows (inside the dumpster). but with a decreased contrast throughout the image and an ever so slight halo around Sears Tower.
The goal here is to retrieve more details in highlights and shadows while preserving contrast. But people do tend to overuse the tonemapping feature to generate surreal images, because of the initial wow factor.
By the way the HDR tonemapping generated by Photomatix 3.1.2