Change photo background and increase resolution

I would like to change the background of the first photo to the background of the second photo. Please note the second photo background must be as it is to include the flag and a high resolution, if possible I would like to have my mouth closed on the picture that needs to be edited. I had to reduce the file size of the second picture as it was 8mb and i could not upload on here. Please note the final result must look natural and not just photoshopped. Thanks