Bluesky Image Size Guide 2026 — Posts, Banner, Avatar
Complete Bluesky image size cheat sheet for 2026: post images, profile banner, and avatar dimensions. Resize in one click with ShareMint.
Bluesky has unusually strict image specifications compared to Twitter or Threads: each uploaded image is limited to roughly 1MB, the avatar is a tiny 400×400 square (displayed as a rounded square or circle), and the banner uses an uncommon 3:1 ratio (3000×1000). Getting any of these wrong means stretched banners, blurry avatars, or rejected uploads. This guide lists every Bluesky size, and ShareMint exports each one with a single click.
| Placement | Size (px) | Notes |
|---|---|---|
| Post (recommended) | 1000 × 1000 | 1:1 square. Feed shows 16:9 |
| Post (maximum) | 2000 × 2000 | ~1MB per image upper limit |
| Profile banner | 3000 × 1000 | 3:1 aspect ratio |
| Avatar | 400 × 400 | Rendered as rounded square / circle |
Steps
Know the Bluesky sizes
Post images: recommended 1000x1000 (square) or equivalent, with an upper limit of 2000x2000 pixels and ~1MB per file. Bluesky displays post images at 16:9 in the feed. Profile banner: 3000x1000 (3:1). Avatar: 400x400 (1:1, displayed as a rounded square / circle).
Pick the right ratio first
Decide if your post is landscape (16:9), square (1:1), or portrait. Bluesky crops aggressively in feed, so exporting at the right ratio prevents surprises.
Resize in ShareMint
Drop your image into ShareMint and choose the matching Bluesky preset. Apply a focal point on the most important subject so the in-feed crop stays on-target.
Compress to fit the 1MB cap
Bluesky limits uploads to ~1MB. Use ShareMint's WebP output at 80-85% quality to stay under the cap without visible loss.
Upload to Bluesky
Open Bluesky's composer, attach the resized file, and publish. The image will display crisp on web, iOS, and Android clients.
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Resize for BlueskyFAQ
What is the Bluesky image upload limit?
Bluesky currently limits each image to roughly 1MB. WebP at 80-85% quality usually keeps high-resolution photos under the cap.
Does Bluesky support PNG with transparency?
Yes, but transparent PNGs are flattened against a white background in the feed. Use JPEG or WebP unless you specifically need an alpha channel.
What avatar size looks best?
Upload 400x400 square (Bluesky's native avatar size). Bluesky displays the avatar as a rounded square / circle, so keep your face or logo centered well within the frame.
Why does my banner look stretched?
The banner aspect ratio is 3:1 (3000x1000). Uploading a 16:9 image causes Bluesky to crop the top and bottom. Use ShareMint's 3000x1000 preset to avoid this.