Hey r/SideProject 👋
I'm a solo dev and I burned out on paying $30-50 to a freelancer every time I needed a thumbnail, or spending 2 hours myself in Photoshop to get something that still looked mid. So I built Thumby.
The whole thing is built around one idea: you shouldn't need to write a 200-word prompt to get a good thumbnail. Type one line, pick a style, done.
You type something like "my dog stole my pizza", tap a style — MrBeast, MKBHD, Cocomelon, Ms Rachel, Stephanie Soo, and 13 more, all reverse-engineered from real top creators in their niche — and ~60 seconds later you get a finished thumbnail. You can ask for 1 to 4 variants per click, your call. One click upscales to 2K or 4K.
The part I'm most proud of is custom styles. You can lock in your own channel's look once (system prompt + reference images) and reuse it for every video. No more rewriting prompts every Sunday.
Behind the scenes every generation runs through a composition ruleset I update every few months — focal subject 30-50% of the frame, max 3 words of text, mobile-readable at 120px, no shock-face, no text that just repeats the title. Stuff that's invisible to the user but means even a beginner gets something CTR-shaped on the first try.
No subscription. Pay-as-you-go credits that never expire. $15 / $49 / $99 packs. 3 free credits when you sign up, no card.
thumby.app — video below shows the flow start to finish.
Honestly the thing I most want to hear: does the "pick a style, type one line" flow feel obvious to you, or is it confusing? I keep going back and forth on whether to hide the raw-prompt mode entirely from new users.