Bluesky Video and Image Sizes 2026

Bluesky and X (Twitter) compete for the same short-form text audience, and their media specs are close enough that the same content works on both. Here's what differs in their Bluesky image size requirements and X specs.

Image file size: Bluesky enforces a strict 1MB per image limit (AT Protocol constraint). X allows up to 5MB for JPEG and PNG. This is the biggest practical difference — images that upload instantly to X may fail on Bluesky. Always compress to under 1MB before posting to Bluesky.

Images per post: Both platforms allow up to 4 images per post. Display is similar: 2x2 grid for 4 images, side-by-side for 2.

Video: X allows up to 512MB and 2:20 for standard accounts (3 hours for X Premium). Bluesky caps at 50MB and 60 seconds. For short clips under 60 seconds, the same export works on both — just keep it under 50MB. For longer content, X is the only option.

Character limits: Bluesky has 300 characters. X standard is 280. They're close enough to write one caption that works on both with minor tweaks.

Algorithm: X has a complex ranking algorithm that weights engagement, account age, and X Premium status. Bluesky uses a chronological feed by default — posts display in order of publication, no algorithmic sorting unless the user switches to an algorithmic feed. For new accounts, Bluesky organic reach is more predictable.

The practical cross-posting rule: compress images to under 1MB (works on both), export video under 50MB and 60 seconds (works on both), write captions under 280 characters (works on both). One asset, two platforms.

Bluesky is built on the AT Protocol, which is an open standard. This means third-party scheduling tools can integrate with Bluesky without waiting for a closed API program — unlike X, which restricts API access, or Threads, which requires Meta developer approval.

How AT Protocol scheduling works: Apps authenticate with your Bluesky handle and app password (not your main account password — Bluesky has a separate app password system for third-party access). The app posts on your behalf via the AT Protocol API. You can revoke access at any time from your Bluesky security settings.

App passwords: Generate a Bluesky app password at bsky.app → Settings → Privacy and Security → App Passwords. Name it after the tool you're giving access to. Each tool gets its own app password, so you can revoke one tool's access without affecting others.

What schedulers can post: Text posts, image posts (up to 4 images, each under 1MB), video posts (MP4, under 50MB), and threaded replies. The full Bluesky image size requirements and video limits apply to scheduled posts the same as manual ones.

Xroad Studio: Connect Bluesky by generating an app password and entering it in Xroad's settings. Xroad automatically compresses images to under 1MB before posting — the most common failure point for new Bluesky integrations. Schedule Bluesky posts alongside your other platforms from one dashboard.

The most common reason Bluesky posts fail is exceeding the 1MB image limit. Unlike X (5MB) or Instagram (8MB), Bluesky's AT Protocol has a much tighter constraint. Here's how to reliably stay under it:

For JPEG: Export at 80% quality at 1200×630px. Most images land at 200–600KB — well under the limit. Avoid 100% quality exports; they're 3–5MB.

For PNG: PNG files are often too large for Bluesky. Convert to JPEG before uploading unless you specifically need transparency.

Xroad Studio automatically optimizes images for each platform's limits before posting, so you never hit a failed upload due to file size. The 1MB constraint is defined by the AT Protocol spec that Bluesky runs on.