how to get the invert feature from the looks section on the PS Express mobile app to work on my Photoshop elements on my PC?

Hi there, I have a Canon 6D and can wirelessly download my photos to my iPad or Iphone which I occasionally do. However when I do, it does not download as the original , say, 20MB file but as a 1.5MB file. There's a wonderful "negative" invert feature in the looks area of the iPhone PSExpress app but that feature is not available on the Photoshop Express that came with the Windows 10 now reluctantly on my laptop. Is it maybe hidden on Photoshop Elements somewhere where I have not looked? I need to convert a picture to its negative imagine in full resolution. What do I do?

Thanks for helping out...