The ~CR file extension is sometimes used by data recovery software for images that were recovered from memory card or hard drives.
In most cases renaming the ~CR file extension to the original extension (most likely JPEG) should make them accessible by image viewers again. This works because recovery software does not alter the data it recovers, so if it was JPEG it will still be JPEG. Sometimes however, images are not fully recovered and can be damaged (lines, chopped images, squares, error drawing, or no full image, etc.).
This file extension can also sometimes be used for temporary files.