* medium term: provide both capabilities, update via button and istantaneously.
* medium term: modular and external execution of dcraw and Pablo's alignment tool.
* long term: TEST/IMPROVE the antighosting algorithm (Pablo D'Angelo's suggestions)

* http://freenet-homepage.de/hsbosny/HDR_Tutorial/HDR_Tutorial-en.html if exif data is missing let the user select the fstop numbers for each image, and figure out a value for the time.
* http://www.vips.ecs.soton.ac.uk/ a powerful and modular image processing library that supports very large images and multiple processors natively. (to reduce memory footprint)

BYPASSED, PREGAMMA ALWAYS COMPUTED* consider in tonemapping rgb->xyz ... xyz->rgb (it's ugly, though)