Can't save?

[keliz]

So I just downloaded this today and when I try to save, it says: Error save File. Please use psd, jpg, etc extension and i don't really know what that means or how that works. Is there something I need to download? the only other drawing program I've used is krita and it gives you a drop-down bar to give options on what you can save the file as but for paintstorm there isn't any as far as I can tell.

[support]

If you on MAC OS type the extension, for example: myfile.psd (but not just "myfile")