Featured Home Image

Hi all,

I am new to wordpress and not tech savvy at all so please respond as if you were talking to a five year old. I am having a problem, the featured home page image is gigantic, in the sketchthemes admin consol it will not allow me to change the size of the picture, it say this next to the upload button:

“Choose image for home page. Size: Width 1583px and Height 716px”

Here is a link the the site, https://nomisclaimsadministration.com/ I would really appreciate suggestions, I am ready to pull my hair out.

Thanks!