YouTube thumbnails: a practical guide to getting the click

Start with the rules

YouTube accepts a thumbnail up to 2MB, at a 16:9 ratio, and recommends 1280 by 720 pixels as the minimum. Upload under that and the image is either rejected or stretched, both of which cost you clicks before anyone reads the title.

The platform also requires the image to represent the video. A thumbnail that promises something the video does not deliver gets a click and then a fast exit, which is worse than no click at all.

The three elements

Relevance

The image should say what the video is about without the title. If the video is a walkthrough of a specific tool, show the tool. A generic face or a stock photo of a laptop tells the viewer nothing and competes with every other thumbnail on the page.

Clarity at the size it is shown

On a phone the thumbnail is roughly the size of a postage stamp. Two or three words at most, in a heavy weight, with real contrast. Anything smaller disappears. Test it by shrinking the image to 168 pixels wide and looking at it from arm's length.

One idea

The strongest thumbnails carry a single idea: a face with an expression, an object, a number, or a clear before and after. Two competing ideas split attention, and split attention does not click.

What to test, in order

Contrast between the subject and the background. Light background with a dark subject, or the reverse.
Face or no face. Faces draw attention, but only when the expression matches the topic.
Text on the image against no text. Text helps when the title is vague and hurts when it repeats the title.
Colour against the YouTube interface. Reds and warm tones stand out against a white page; white and grey disappear.

Change one of those at a time and let each version run long enough to judge. Changing four things at once tells you nothing.

Where thumbnails fit in the wider account

For a business channel, the thumbnail is the same decision as a display creative: the image either earns attention or it does not. The difference is that YouTube gives you a click through rate on every video, so the test is cheap and the answer arrives quickly.

If a channel has good videos and weak click through, new thumbnails are usually the cheapest fix available. If the click through is good and the watch time is poor, the problem has moved into the first thirty seconds of the video.