please see above to open .dat file, just select

the application (program) you used to open .png file, instead of window media player, such as Photoshop, or MS image viewer, then make sure to check the box that says "always open such file using this program", then next time, just double click PNG file, you will see the image.

To change the regional, should not change this "hot link". anyway, this procedure should re-build the hot link again.