Larger header image or non-adapting possible?

Hi, thanks for the awesome theme in first place.

I have a question: is it possible to use a header image wider than 1200px? I’m trying to use one which is 1920px wide, but it gets cropped. I saw that the theme expands the header according to the window size and I’d like it to be prepared for higher resolutions so it doesn’t loose quality.

Alternatively, would it be possible to leave it size-fixed independent of the window size?

Also, is it possible to remove the previous uploaded headers? I can’t find where to remove them but would love to use the random option.

Thanks!