I don't use Photoshop much anymore since I no longer run Windows. I'll have to see if The GIMP has those features. Otherwise, I may be able to do this manually as I have done on a few photos before, though I don't think I can find those files.
I didn't know what HDR meant. Here is an explanation from one perspective. Examples can be seen at the link.
- HDR: HIGH DYNAMIC RANGE PHOTOGRAPHY -
High dynamic range (HDR) images enable photographers to record a greater range of tonal detail than a given camera could capture in a single photo. This opens up a whole new set of lighting possibilities which one might have previously avoided—for purely technical reasons. The new "merge to HDR" feature of Photoshop CS2 allows the photographer to combine a series of bracketed exposures into a single image which encompasses the tonal detail of the entire series. There is no free lunch however; trying to broaden the tonal range will inevitably come at the expense of decreased contrast in some tones. Learning to use the merge to HDR feature in Photoshop CS2 can help you make the most of your dynamic range under tricky lighting—while still balancing this trade-off with contrast.
A few sample images can be seen here