First, what created the .jpx file?
Is that directly from the camera?

To be honest, I hadn't heard of that file type before reading this, so I did my normal Google search and read up that its an advancement on the JPEG codec line. That didn't tell me a whole bunch, I don't have any photos in that format to see how it works or if it will load.

On my search, I did find many different converters (search: .jpx to .jpg converter). so there is a lot out there.