Quoting David Heino :

There's much talk recently about HDR images. Could someone with more technical expertise than I possess comment on HighDef television and whether there will be soon something like a HighDef computer monitor? Specifically, for a long time I have been making images for web content at 72 dpi under the assumption that it is the highest resolution needed for display on the computer screen. Will this soon change? And, if so, what sort of resolutions will be needed? How will this change the production of images for web content?

HDR imaging and HDTV are quite unrelated. The "high definition" in HDR is in reference to the color depth of the individual pixels while for HDTV it is referring to the pixel density of the image.

The GIMP currently supports up to 8-bits per color per pixel 'color depth' while HDR imaging generally requires 10 or more (usually the jump is made to 16- or 32-bit color depths; and the use of floating point representation in some formats). Computer monitors and HDTV only requires 8-bit colors and so the images that the GIMP produces are quite satisfifactory for that purpose (and the "pixel density" aspect of HDTV is basically irrelevant). The need for greater color depths arises when _editing_ the images.

Many cameras and scanning devices provide data that employs deeper color depths and the GIMP is currently unable to handle that extra information; it would be discarded when the data is imported from the device (or HDR file). Note that this information would also be "discarded" when sent to the monitor or HDTV (which only handles 8BPP depth) but it is useful during editing to have that information.

The situation is very similar to that of audio editing and production: even though the sound quality of CDs is limited to 16-bit samples sampled at 41100Hz, it is beneficial to handle higher quality versions (24-bit at 96kHz, for example) during the editing process.