cannot edit meta data on BMP files. why??

Im trying to edit the metadata on some image files that are .BMP and it will not allow me. I get the error code:" This property cannot be modified." They are my images. and while I cannot edit the meta data of the .bmp files, I CAN edit the JPG versions of the exact same images. Whats up? and no, it is not an issue of the under preferences and thumbnail changing the processing size to something higher. These files are well under the range able to be processed.

any help greatly appreciated.