Blog
Notes on making YouTube thumbnails. Every specification here was checked against its source, and each article carries the date it was last checked.
What affiliate programmes actually pay creators
Recurring or one-off, a percentage of what, cookie windows versus codes: the arithmetic behind an affiliate offer, and what to ask before you promote one.
Thumblify Team·9 min read
AI thumbnails on 50 YouTube videos: what happened to CTR
We ran 50 tests of AI-generated thumbnails on live YouTube channels across 10 niches, and click-through rate rose by 38% on average.
Thumblify Team·8 min read
The thumbnail tools that cost no credits, and their limits
Title suggestions and the prompt enhancer cost no credits and are capped at 40 calls an hour each. Only generating an image draws the balance down.
Thumblify Team·5 min read
Does Thumblify have a free trial? Trial vs free plan
A 14-day trial of a paid plan needs a card and hands over the whole monthly allowance at once. The free plan needs no card and watermarks what it makes.
Thumblify Team·7 min read
How to put your face on a thumbnail: 25 or 100 credits
Two routes: attach a photo to a generation from 25 credits, or swap your face into a library thumbnail for 100. The photo is sent once and stored nowhere.
Thumblify Team·4 min read
How to recreate a thumbnail style and change one thing
Recreate takes a thumbnail from the public library and applies one described change to it: 50 credits, one image, on any signed-in plan.
Thumblify Team·4 min read
Thumbnail export resolution: 720p, 1080p or 2160p by plan
The height you get depends on the plan, not the model: Free exports 1280x720, Basic upscales to 1080p, and Pro and Elite upscale to 2160p.
Thumblify Team·5 min read
How many credits a thumbnail costs: 20 to 200, per image
Thumblify charges per generated image: 20 credits on Standard up to 200 on Ultra, multiplied by the number of variants requested.
Thumblify Team·4 min read
YouTube Shorts thumbnail size: 2160 x 3840, desktop only
YouTube documents 2160 x 3840 at 9:16 with a minimum height of 640, and a custom Shorts thumbnail can only be set in Studio on a computer.
Thumblify Team·5 min read
YouTube thumbnail A/B testing is decided by watch time
YouTube's Test and Compare picks the winner by watch time, not clicks. Up to three options, two weeks, desktop Studio only, and no Shorts.
Thumblify Team·6 min read
YouTube thumbnail not updating: what YouTube documents
YouTube publishes no propagation time for a thumbnail change. The one delay it does document is on Facebook and X, and there is a tool to clear it.
Thumblify Team·6 min read
Best AI thumbnail maker: 10 tools compared on price
Ten tools for making YouTube thumbnails with AI, checked against each tool's own pricing page. Where a figure could not be read, it says so.
Thumblify Team·20 min read
YouTube thumbnail size: 3840 x 2160, and a 50 MB limit
YouTube now recommends 3840 x 2160 at 16:9 and allows 50 MB from desktop. The figures most guides still quote were superseded in October 2025.
Thumblify Team·7 min read