Currently, open HDR image file formats (Radiance HDR, OpenEXR) are not supported on Wikimedia Commons (see http://commons.wikimedia.org/wiki/Commons:File_types). It is important to allow users to upload images in one or both of these file formats, for the following reasons:
- HDRI is a rapidly developing field, and it is expected that HDR images will become far more common in the following years.
- To my knowledge, there are no HDR images on the web which have been published under a free license, nor are they allowed by Flickr. Allowing HDR images would be a great opportunity for Commons to establish itself as the main source for them.
- At the moment, we only have a category for tonemapped HDR images (http://commons.wikimedia.org/wiki/Category:HDR_images). Most of these images were obviously generated using a bad tone mapping operator or simplistic image processing techniques, as can be seen from the halo artefacts. With HDR images, users could not only recover the full dynamic range of photos and computer graphics, and change the exposure without any loss, but also use any tone mapping operator they want.
One issue is the preview/downscaled image to provide. I suggest that the preview/downscaled image be generated from the HDR image using a robust tone mapping operator, such as Ward's histogram adjustment technique (http://radsite.lbl.gov/radiance/papers/lbnl39882/tonemap.pdf).