I really like the HDR option of the Windows phone camera app. Therefore I tend to use it almost as default. Sometimes when I later go through the photos I have taken I find some where the HDR mode doesn't really improve the image. Is it possible to convert these photos to "normal" so that they use less space?
The HDR mode takes multiple exposures upon pressing the shutter button. These exposures are stored in a .NAR file (same filename as the photo, but different extension) in your Camera Roll folder. If you want to free up disk space, simply use the File Explorer app to delete the .NAR file. This will leave the .JPG file containing the photo intact, just make sure you're happy with it first.