851 x 315 pixels
851 by 315 px is a 851:315 landscape image. 851 divided by 315 is 2.7016, and the fraction reduces exactly to 851:315. It is 0.27 megapixels (268,065 pixels) with a diagonal of 907 px. 1 image size on this site uses it.
Who uses 851 x 315
| Platform | Asset | Role | Source |
|---|---|---|---|
| Cover photo | Recommended size | Documented |
What the numbers mean
The pixel count is what the file stores. It is not the size the image appears at on a screen, and the two get confused constantly. A display measures its layout in CSS pixels, and most phones draw two or three physical pixels for every CSS pixel. That device pixel ratio is why an avatar that occupies 110 CSS pixels wants a file several times wider: on a 2x screen those 110 CSS pixels are 220 physical ones, and a 110 px file gets upscaled to fill them.
So 851 by 315 is a statement about the file, not about how large it looks. Whether it is enough depends on the largest surface it has to fill and on the pixel ratio of the screen filling it, which is why the platform pages above carry a minimum width as well as a recommended size.
Resize an image to 851 x 315
Preloaded to this exact size. It runs in your browser, so nothing is uploaded anywhere.
Closest other sizes
Nearest by shape, so a crop between any of these loses the least. Sorted by how far each one is from 2.7016.
Every size on one page: the cheat sheet. Last verified 2026-07-27.