Keeping in mind only landscape images, and YouTube videos, (since vertical images can create unwanted large spaces) the homepage banner background image should be preferably:
16:9 aspect ratio, with a minimum of 1920 x 1080 px
# File Size (Weight)
Aim to have files with less than 500kb in file size for better SEO.
Our file upload supports files up to 8Mb, but this is not recommended. If they have an image they really like they can shrink the image using this site: https://tinypng.com/
# Supported formats:
BMP, GIF, JPEG, PNG, WebP, SVG, and AVIFExtra
Image banks with royalty free images: