Support are usually pretty good at responding.
FYI DMG format files are Mac archives. Probably created with a software like Stuffit (http://www.stuffit.com) Not readable on Windows.
OR
It's a Digital Negative Graphic file
http://www.fileinfo.com/extension/dng
On the above page are lists of programmes which will open that kind of file which, if you have, you can open the file then save it to a format which PP will open/read.
FYI DMG format files are Mac archives. Probably created with a software like Stuffit (http://www.stuffit.com) Not readable on Windows.
OR
It's a Digital Negative Graphic file
http://www.fileinfo.com/extension/dng
On the above page are lists of programmes which will open that kind of file which, if you have, you can open the file then save it to a format which PP will open/read.