File/New...
Creates a new image. A new window will be shown where you can select the image size from 2x2 to 256x256. You also have the option to keep the current palette, or to load a new one. See New image window.
File/Open...
Loads a new image. It can be one of the supported formats. See Supported image formats
File/Save
Saves the current image in a file. If the image hasn't been saved before it behaves the same as File/Save as
File/Save as...
Saves the current image with different name. The Save image window will pop up where you can select the image format to be used for saving.
File/Exit
Exits the application. There is no confirmation asked, so when you select this command the program will exit immediately. But since the session is automatically saved (see Sessions) when you restart the application the image will be restored as well (except if you removed the memory card).