I use Gimp 2, an open source alternative program to Photoshop. When I use the program it automatically assumes I want to save it in .xcf
format. What you should try to do is ... when you save the picture file ... see if the program has a "save as"
feature. Use that instead of save
. When it gives you the file name and asks for you the where you want to save it ... manually delete the .php file extension and type in .jpg.
This works for Gimp 2. For Gimp 2, it will ask me if I want to export the file format to .jpg. Confirm the desire to change the format. Gimp 2 then asks me if I want to compress the file or keep the same level of image quality. I opt for 100% quality transfer (no compression).
And booya! It's a jpg!