...

• Use the folder/explorer to see what mount you are viewing

...

If the image doesn't mount, use disktype to detect image format

1. Open a Terminal (CTRL + ALT + T)
2. Navigate to a disk image with:
   • cd to change directory: cd Desktop/myfolder
   • ls to list files and directories: ls
3. Run disktype
   • disktype myimage.dd 
4. View output:

...