You can find these in the dconf-editor application, then using the "Set to Default" button to reset each desired entry. dconf-editor can be installed at the command line with sudo apt-get install dconf-tools.
Otherwise, you could also try resetting any one of the locations by using the following command in the terminal:
Some but unfortuanley not all of the keyboard shortcuts are listed in the GNOME Image Viewer Manual that you will also get by pressing the "Help" button in Eye Of Gnome.
Keyboard shortcuts that are not listed may appear in the menu dropdown list (e.g. Ctrl+R for rotating clockwise or Shift+Ctrl+R for rotating counter clockwise).
Best Answer
To display the keyboard shortcuts, hold the "Super" key--most likely the Windows key, unless you have a Mac, in which case I don't know.