Why your image gets cropped on social media, and what size to use

You spend time on an image, post it, and the platform crops the top off. Or it pads it with grey bars. Or the text you added is suddenly soft and blocky. It feels arbitrary, and it is not.

Every platform reshapes uploads to fit a layout designed long before your image existed. Once you know what they are doing, preparing images that survive becomes straightforward.

Aspect ratio is the whole problem

Almost every cropping complaint comes down to one thing: the shape of your image does not match the shape of the space it is being poured into.

A platform showing a square feed cell cannot display a tall portrait image without a decision. It either crops the top and bottom, or shrinks the whole thing and pads the sides. Which one it chooses varies, and it can differ between the feed, the profile grid and the full view of the same post.

This is why an image can look correct in one place and wrong in another on the same platform. You are not seeing your image. You are seeing several different crops of it.

• Square, 1:1: safe in feeds almost everywhere
• Portrait, 4:5: uses more vertical space in mobile feeds without being cropped by most
• Landscape, 1.91:1: the standard for link previews and wide cards
• Vertical, 9:16: full-screen stories and short video formats
• Anything taller or wider than those: expect cropping or padding

The safe zone principle

Rather than memorising dimensions for every platform, design with margins. Keep anything that must be readable — text, logos, faces, the edge of a product — inside the central portion of the image, and treat the outer band as expendable.

A margin of roughly ten percent on each side absorbs most platform cropping. If the image is going somewhere with a circular crop, such as a profile picture, keep the subject inside a central circle rather than a central rectangle.

This one habit removes most of the frustration, because it means you no longer need to know exactly how a given platform will crop. Whatever it takes from the edges, the important part survives.

Why the quality drops

Platforms re-encode every upload to control bandwidth. Your file is decompressed, resized and compressed again with their settings, not yours. You cannot prevent this, but you can make it hurt less.

1. Upload at or slightly above the display size, not far above. A 6000 pixel wide image displayed at 1080 is aggressively downscaled, and fine detail does not survive.
2. Upload the highest quality version you have of that size. Do not pre-compress heavily, since the platform will compress again and the two losses compound.
3. Avoid thin text and fine lines, which are the first things re-encoding destroys.
4. Prefer solid backgrounds behind text rather than busy photographs, since compression handles flat areas well and detailed ones badly.
5. Check the result on a phone after posting, not just on your desktop.

The second point catches people who compress carefully before uploading to save time. Compressing a file that is about to be compressed again produces visibly worse results than uploading a clean version once.

Link previews are their own thing

When you share a link rather than an image, the preview card comes from tags in the page rather than anything you upload. The conventional size is 1200 by 630 pixels, and platforms are stricter here than in feeds: too small and the card renders as a small thumbnail, or without an image at all.

Previews are also cached aggressively, often for weeks. If you change the image and the old one keeps appearing, the platform is showing you a stored copy rather than fetching again. Sharing the address with a query string added is the quickest way to see the current version, since the different address is treated as a new link.