Last updated: September 2026
What is Bluesky's image size limit in 2026?
2MB per image, which means 2,000,000 bytes. Bluesky doubled the limit from 1MB in April 2026. You can attach up to 4 images to a post, and alt text can run up to 2,000 characters in the app.
If a guide tells you 1MB, it predates the change. Here is what changed, how it compares with X, and what to do with a file that is still too big.
What changed in April 2026
TechCrunch reported on April 23, 2026 that Bluesky, which had only supported photo uploads of 1MB or less, doubled the limit to 2MB with version 1.121 of its app. The same update made photos render at up to 4000px instead of 2000px, and replaced the old image grid with a swipeable carousel that handles mixed aspect ratios without cropping. Source: TechCrunch, "Bluesky now supports better-quality photos".
2MB means 2,000,000 bytes
Operating systems that count in 1,024s will show a 1,990,000-byte file and a 2,050,000-byte file as roughly the same size. Only the first one uploads. Check the exact byte count, or drop the file into the Bluesky image checker.Bluesky vs X image limits
As of September 2026. Both networks take up to 4 images per post, so a cross-post never has to drop an image for count. Size is where they differ: an image between 2MB and 5MB fits X and not Bluesky.
Alt text runs the other way: Bluesky allows up to 2,000 characters in its app, X up to 1,000. If you write long descriptions, write for X's limit and they fit both.
If your image is over 2MB
- Export as JPEG or WebP rather than PNG for photos. PNG is lossless and is usually the reason a photo is too big.
- Resize to 4000px on the long edge. Since April 2026 that is the largest Bluesky renders, so extra pixels only add bytes.
- Lower the export quality a step at a time and check the exact byte count after each export.
- Keep screenshots and diagrams as PNG, but crop them to what matters before exporting.
For cross-posting, size the image for Bluesky first. A file under 2,000,000 bytes is also well under X's 5MB, so one file works on both.
Images through OpenTweet
OpenTweet publishes up to 4 images with alt text to both X and Bluesky from one draft or one API call, working to the 2,000,000-byte limit on Bluesky and 5MB on X. Video goes to X only: OpenTweet does not publish video to Bluesky. The guide to posting on X and Bluesky at the same time covers the text limits, and the Bluesky scheduler covers scheduling.
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Frequently asked questions
What is Bluesky's image size limit in 2026?
2MB per image, which is 2,000,000 bytes. Bluesky doubled it from 1MB in April 2026, alongside app version 1.121. You can attach up to 4 images to one post.
Is 2MB on Bluesky 2,000,000 bytes or 2,097,152?
Plan for 2,000,000 bytes. A file your computer shows as 1.95MB can be over 2,000,000 bytes if the computer counts in 1,024s, so compare the exact byte count rather than the rounded size.
How many images can a Bluesky post have?
Up to 4. Since the April 2026 update the app shows them in a swipeable carousel that handles mixed aspect ratios without cropping.
How long can Bluesky alt text be?
Up to 2,000 characters in the Bluesky app, as of September 2026. X allows up to 1,000, so alt text written for Bluesky may need trimming for X.
Can I post video to Bluesky through OpenTweet?
No. OpenTweet publishes images to Bluesky but not video. A cross-post with video still publishes on X, where video is supported.
Keep exploring
Size for Bluesky first and one file works on both networks.
Bluesky image checker
Drop in an image and see whether it clears 2,000,000 bytes before you post.
Post to X and Bluesky at once
Three routes, the limits that differ, and one curl that does both.
Does a link count on Bluesky?
Yes, at full length via the API. Spaces count too.
How to cross-post to Bluesky
Connecting your handle and sending the first post to both networks.
Bluesky scheduler
Schedule Bluesky posts, images and threads over atproto OAuth.
Cross-posting to X and Bluesky
One draft, a native post on each network, and a per-network result.
Images on X and Bluesky, one draft
Up to 4 images with alt text on both networks. From $11.99 a month.
7-day free trial. Cancel anytime.