I would like help with the header image please

Hi.

I would like to ask for help with the following.

I like everything about this theme but I would like to know how to change the Header Image. After uploading the recommend size the image seems to be in shadow and is not the right size to fit the template? I would also like to disable the parallex (scrolling??) feature

I would like to simply use a static image for the header.
Could anyone advise if this is possible?

Thanks in advance. Lowri