help off-center image

I mean that gray area in the first image that does not allow to see completely.
in the second image is when I modify the CS6 to full screen or full screen to window (this is how it should be)

PS: and one more question, can you configure that the format in which I save the photos is by default in JPEG? and not photoshop format, but I must change it manually in each photo

Just a thought, but if you mean that part of the image is being hidden behind panels, then you could try making sure that Overscroll is checked.  Your Preferences are going to look different, but it should still be under the Preferences > Tools tab/

It's important for you to understand:

1) CS6 is discontinued and unsupported (it is what it is).

2) CS6 doesn't understand Hi-DPI displays and never will.

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Just use Ctrl+0 menu View>Fit On Screen so you can see the full image then use the crop tool. The image can be anywhere on your display.