VQMod: Make sure you have VQMod installed.

Copy 'Admin_Order_with_Image.xml' to /vqmod/xml/ . No file need to edit or replaced.

OCMod:
Go to your OpenCart admin panel > Extensions > Extension Installer.
Click the Upload button and select the Admin_Order_with_Image.OCMod.xml file.
You should get a green message saying: "Success: You have installed your extension!".
Now navigate to Extensions > Modifications and click on the Refresh button at the top right corner of the screen.

It may not work with custom template.

Find more extensions from http://www.opencart.com/index.php?route=extension/extension&filter_username=cathyshea