Google Image. What're you looking for, specifically?
I actually rather like concept art from movies or video games -- they tend to be panoramic and rather scenic, though not completely devoid of action or theme. My current desktop is a concept art from Assassin's Creed 4 (a pirate game, apparently) ...
Vintage ones like of old signage, old buildings, scenic is good but I really like the vintage vibe of old scenery if that makes sense.
You might take a look at William Eggleston's, Garry Winogrand's, and Robert Frank's work if photographs from the mid-century (and later) will pass for "old". There's a photo archive called Shorpy that covers a lot of ground, and the HistoryPorn section of Reddit has its moments, though it tends to lean toward military subject matter. Retronaut is a large and varied site.
I spend a little time here and there monkeying around with images to wallpaper-ize them -- talk about cheap entertainment -- and find the Microsoft Office Picture Manager hard to beat (if you've Office and nothing better) for trimming and magnifying and so forth.
I just googled "free vintage photography," and got this.
What about technology. like old trains crossing landscapes?
I copied a bunch of the motivational posters from AoM into a folder and set the desktop to cycle through them, along with a bunch of other pictures. Teddy Roosevelt, Winston Churchill, Gen. Patton, and others.
I view those as kind of screaming "look how manly I am".
Don't mind it on FB, as that's what it's for, but on one's own desktop; that seems narcissistic to me.
Here ya go ...