3440x1440 Ultra-wide resolution help

I am new here and I see there are lots of amazing photo’s. It inspires me to get my own shots soon and put more time & effort into astronomy and a bit less into late night gaming sessions. Anyway if it is allowed, I’d love to use some of these as background images for my Ultra-wide Alienware PC monitor (3440×1440 display resolution), how would I go about resizing peoples (landscape orientated) photo’s to match my display resolution on those that don’t start out at that specific resolution when uploaded to astrobin? I was hoping there are some other users who edit photos from this website into 3440×1440p background images who could advise me on the best apps/ methods they use. Or better still, do any photo’s get uploaded at this display resolution to begin with? Thanks 🙂