Saving the image
Click the Save icon on the main toolbar or select the File->Save item in the main menu to save the changes you have made to the current file. This command is also accessible from right-click context menu (in some modes) and via Ctrl+S shortcut.
Save As command
1. Click the Save As icon on the main toolbar or select the File->Save As... item in the main menu or Save As... item in the context menu to save the current image with a different location or filename. You can use the Ctrl+Shift+S shortcut for this command.
2. Using the Save As dialog, browse to the folder where you want to save the image and enter the name under which you would like to save it into the File name field, or select the existing file if you wish to replace it with the current image.
3. Click the Save button to save the current image under the new name, or double click the existing file if you want to replace it.
You can change saving preferences in File->Preferences->Saving Pane.