There are 2 ways to save current image file on disk:
1.Rewrite current file on the disk. To do this, select in the main menu: File -> Save.
2.Select another name, path or format. To do this, select in the main menu: File -> Save As...
Or simply click at the following button on toolbar:
Here, on the Save File dialog, you can specify new name for the file, and specify output image format.
If you want to configure output parameters, click at the button "Advanced...".
You will see the window where you can specify parameters of selected format:
Click "Preview" button to update the Result Preview according to your changes.
Click "OK" to save the changes.