YouTube thumbnail tester
See your thumbnail the way viewers do — at sidebar and phone size, without colour, and blurred — before it is the thing your video is judged by.
Nothing is uploaded — the image stays in your browser.
Three tests worth doing
- Shrink it. If the text is unreadable at 168 pixels, it is unreadable in the sidebar — cut words until it survives.
- Drain the colour. Contrast carries a thumbnail further than saturation. A design that only works in colour loses next to one that works in both.
- Blur it. What remains recognisable is what a scrolling viewer registers. A face, a number, one object.
The specs
1280×720, 16:9, under 2MB, JPG or PNG. Upload a larger file and YouTube rejects it; upload a smaller one and it gets upscaled on desktop and TV, which reads as amateur before anyone has considered the design.
Consistency beats novelty
A viewer who watched you once should recognise the next thumbnail in half a second. The channels that grow reuse a layout, a colour and a face position — the content changes, the frame does not.
The thumbnail is half the click
The other half is a video people wanted. PostLink analyses the comments on any video and surfaces the videos and titles most likely to break out with that audience.
Analyze a video freeQuestions
What size should a YouTube thumbnail be?
1280×720 pixels, 16:9, under 2MB, as JPG or PNG. Anything smaller looks soft on desktop and television; anything in a different shape gets cropped.
Why preview it small?
Almost nobody sees a thumbnail at full size. In the sidebar it is about 168 pixels wide and on a phone it is smaller still, which is where four words of text turn into a grey smear.
What does the greyscale view tell me?
Whether the image works on contrast rather than colour. If the subject disappears without colour, it will also disappear next to a competitor thumbnail that uses a stronger tonal split.
And the blurred one?
It approximates a glance. Viewers scroll past at speed, so the shape that survives blurring is the shape they actually register — usually a face or one large object, rarely a sentence.
Is my image uploaded anywhere?
No. Everything happens in your browser; the file never leaves your device.