Time to make use of that little folder you keep on your computer. You know the one. It's full to bursting with fantasy art that you have every intention of using as play aids, inspiration, character portraits, etc. Or maybe you're a psychologically healthy human being who doesn't compulsively hoard gig upon gig of monsters, swords, and monsters with swords. In that case, google "Fantasy Art" and go nuts.
First, create some folders for your top-level table. Give them descriptive names with numbered prefixes, like "1-People," "2-Places," "3-Things" and "4-Events." Yeah, I expect you're way ahead of me now, but let's continue.
Within each of those folders you'll create more specific categories, also numbered--and you can nest as deep and get as specific as you like. Maybe you just want to separate character portraits from monsters, or maybe you want to get super granular. You do you, buddy. Once you're satisfied, sort your collection of images into the appropriate folders, then go in and rename each with a numbered prefix and you're all set.
Roll for (or choose) which folder to open. Repeat as necessary, depending on how deeply you nested your folders. Use a dice app that lets you input a whatever-sided die, and roll for a random image. Look at that image and pull something from it that you can build on. Roll multiple times if you like.
Using mine to fill in a hex, I started by rolling a d4 to see how many images I would try to incorporate, and I got a 3. First roll pulls up a monastery-like structure. Second roll is a skeleton in crusader armor. Third is a set of thieves' tools. One thing I like is the opportunity to do some free-association, both because it's fun, and because it's good practice for improvisation at the table. So, thinking on my pictures, I stock the hex with a secluded cult that raises skeletons that can use thief skills, which they send out to rob rival temples.
And that's it. Let me know if you make use of it, and how it works out.