New to Paint.net. INstalled and downloaded the HD Plugin. I loaded a standard JPG from my camera. Tried to save as HD photo and I get an unspecified error. I have .NET 1,2,& 3.5 installed. WinXP Media Center SP3. Also your Plugin doesn't support 48bit or 64 bit. Would be nice. This format has been approved by the Joint Photo Experts Group and will be incorporated as JPEG XR. As pointed out earlier, the format has nothing to do with 'hidef' or even really large megapixel images. From what I have read at the JPEG website, it has more feature like embedded ICC profiles, multiple images per file and better compression with better image.