The file extension JXR marks image files in the so-called JPEG XR format. It is a format developed by Microsoft for its own media software. It supports 48-bit RGB color depth and also provides lossless compression. Originally called HD Photo and Windows Media Photo (hence sometimes also hdp, wdp), it was later introduced as JPEG XR in collaboration with the JPE Group.
Microsoft offers the format for free, so it can be used and implemented by anyone. Many programs today can handle JPEG XR files. However, the extension JXR is used relatively rarely. Much more often you can still see hdp and wdp, the second is registered under Windows 7 for the photo display.
Therefore, it is also useful to look in the file dialogs of the graphics programs for hdp and wdp and rename the JXR file, if necessary, or to open the file via drag and drop (drag from Explorer to the workspace of the graphics program) on a trial basis.
Some programs (Photoshop, Paint.Net) require a plugin (HD-Photo-Plugin) to read these files.
Most often resolving problems with opening JXR files is very simple. Just install an appropriate program that supports such files. All of the listed programs support JXR files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of JXR files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate JXR files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the XnView applications is not on the list, select "Browse" option in order to manually locate the directory where XnView has been installed.
Sometimes problems with opening JXR files may not lie with the application itself, but can arise due to other causes, such as: