skwish

private

browser-based

Fit a repository social preview into GitHub's 1MB, 1280x640 box

The social preview is the only image that decides how a repository looks when somebody links it on Slack, X, LinkedIn or Discord, and GitHub publishes a tight spec for it: a PNG, JPG or GIF under 1MB, at least 640x320 pixels, with 1280x640 recommended for best display. PNG with transparency is supported, which is a trap as much as a feature — a 1280x640 transparent PNG with a large logo and a gradient background lands well over 1MB, the upload rejects it, and people conclude the image is too big when the actual problem is the container format. Two reliable fixes: export as JPEG when the background is solid or a photo, or keep PNG but flatten and quantise the colours. Either way the constraint is 1MB, not 12 MB, so the target is aggressive compared with a README screenshot and worth checking before you open the upload dialog. The 1280x640 aspect ratio is also 2:1, wider than the 1.91:1 that most social platforms crop to, so put the wordmark and the important text inside the safe middle rather than at the edges. Skwish compresses PNG, JPG and WebP in the browser with a live before/after number, so you can confirm the file is under 1MB before uploading. Nothing leaves your machine.

Search match

This page is tuned for compress github social preview image so visitors land in the right workflow immediately.

Fast output

See original size, compressed size, and percentage saved before you move on.

Batch ready

Compress multiple files and pull the results down as a ZIP.

Get to the compressor fast

Exact-intent SEO page first. Clear next step. Pretty later.

People usually search for a specific task, not a brand story. So this page keeps the promise simple: compress images without sending them to a third-party server.

Built for people searching “compress github social preview image”, not a generic landing page.

No uploads, no accounts, no waiting on a server.

See the savings before you download anything.

Batch export stays available when the job is bigger.

Best for this search

Get a 1280x640 social preview under GitHub's 1MB ceiling when the transparent PNG export comes out far heavier.

Convert a transparent PNG social card to JPEG when the background is solid and the alpha channel is only adding bytes.

Check the exact byte size of a social preview before uploading, instead of guessing whether the uploader will accept it.

Compress images now

Opens the upload box on the free browser compressor.

Drop images in the browser

Keep the whole workflow local. Nothing leaves your device unless you download it.

Set the output you need

Adjust compression until the file size and quality fit the job instead of guessing.

Download a clean result

Save one file or a ZIP bundle with skwish-prefixed names so the output is easy to find.

The 1MB cap is the whole constraint

Use these before you upload or share the page.

GitHub accepts PNG, JPG or GIF under 1MB, minimum 640x320, recommended 1280x640. Anything heavier is rejected at upload, not downsized for you.

Transparency is supported but expensive. A transparent 1280x640 card is often two to four times the weight of the same design on a solid background.

2:1 is wider than most platforms' 1.91:1 crop. Keep the wordmark and the key text away from the left and right edges.

Ready to compress images?

Open the free browser upload box, keep files local, and download the optimized result.

Compress images now

Related tools

Other compression pages built for specific size limits and formats.