You can close an image by clicking on the x’ located in the upper right corner of the image window or by selecting Close in the File menu. If you have changed the file since opening it, or if the image is a new file, you will be prompted to save your image before closing. Clicking on Yes will save the image or bring up the Save As dialog for an image that has not previously been saved. Clicking No will close the image without saving. Choosing Cancel will neither save nor close the image; you will be returned to the program window.
Before closing an image, you can manually save the file to your hard drive using the Save or Save As command.