Problem with the crop images

Hi there, I would understand how can I crop the image adapting the original frame to the layout that I’m trying to use.
Basically I’m reducing the frame at Half 3:1 but the problem is that the image is only cut in the middle and I need the full image but reduced.

It’s sounds quiet wired to me that such a simple thing is becoming harder and harder.
I hope that’s my bad….well, I’m sure that’s my bad because it’s very very strange, isn’t it?

Anyone could help me?

Thank you very much