If you want to save a file in another format, use the Save As command.
To save a file:
Choose File > Save As or press F12 to open the Save As dialog.
Navigate to and open the folder in which you want to save the image file.
To rename the image file, type a new name in the File name box.
Open the Save as type box, and scroll to select a new format.
If the file format has save options, click the Options button to open the Save Options dialog. Select new settings, if appropriate. If you are unsure of the settings, use the default values. Click OK to return to the Save As dialog.
Click Save to save the image file and close the dialog.
Saving an Image File in its Original Format