Bluesky Banner Sizeand Avatar Tool
The Bluesky banner size is 3000 by 1000 pixels, a 3:1 strip with your avatar over the bottom left. Crop the banner and a 1000 by 1000 avatar from your photos, and make Mastodon versions too.
Drop a photo here
JPEG, PNG and WebP work everywhere; HEIC opens in Safari. You can also paste a screenshot.
Never uploaded. It all happens in your browser.
You get 4 sizes
- Profile banner3000 × 1000
- Avatar1000 × 1000
- Header image1500 × 500
- Avatar400 × 400
Your files stay on this device. Nothing is uploaded, and location data is removed from every export.
Every size, in full
The tool exports these exact pixel sizes, and compresses a file only when the network has a size limit.
| Size | Pixels | Shape | File |
|---|---|---|---|
| Bluesky profile bannerYour avatar covers the bottom left of the banner on every screen. | 3000 × 1000 | 3:1 | PNG or JPEG, under 1 MB |
| Bluesky avatar | 1000 × 1000 | 1:1 | JPEG or PNG, under 1 MB |
| Mastodon header imageMastodon servers scale headers to 1500 by 500 and cap them at 2 MB unless your server says otherwise. | 1500 × 500 | 3:1 | PNG or JPEG, under 2 MB |
| Mastodon avatar | 400 × 400 | 1:1 | JPEG or PNG, under 2 MB |
How it works
- 1
Upload your images
Choose a banner image and a photo for your avatar. They open in your browser and are never uploaded.
- 2
Clear the avatar
Move the banner so text sits clear of the avatar, and frame your face inside the avatar circle.
- 3
Download each size
Save the Bluesky banner and avatar, and the Mastodon versions if you use both.
Bluesky and Mastodon profile images
Bluesky shows your banner at 3:1 across the top of your profile and puts your round avatar over its bottom left on every screen. Keep text to the middle and right. Upload at 3000 by 1000 pixels so it stays sharp on large screens.
Bluesky caps banner and avatar uploads at 1 MB each, less than most networks. A detailed PNG at full size can go over, so a photo banner is often better saved as a JPEG.
Mastodon headers are 1500 by 500 pixels, also 3:1, with the avatar over the bottom left, and most servers cap uploads at 2 MB. Avatars are 400 by 400 pixels. Each server can set its own limits, so check its about page if an upload fails.
Questions
- What is the Bluesky banner size?
- 3000 by 1000 pixels, a 3:1 strip, under 1 MB. Your avatar covers its bottom left on every screen.
- What size is a Bluesky avatar?
- 1000 by 1000 pixels, shown as a circle, under 1 MB.
- What is the Mastodon header size?
- 1500 by 500 pixels, also 3:1. Most servers cap headers and avatars at 2 MB, and avatars are 400 by 400 pixels. Your server can set its own limits.
- Can Posty schedule posts to Bluesky and Mastodon?
- Posty publishes posts to Bluesky, with up to 4 images each. It does not publish to Mastodon.
- Is my image uploaded anywhere?
- No. Your image opens in your browser and is processed on your own device; it is never sent to Posty or anyone else. Saving a download re-encodes the image, which also strips the EXIF data your camera stored, including GPS location. You do not need an account.
More tools
Every tool runs in your browser, with nothing to install. See all tools
- Twitter headerCrop an X header with the trimmed edges and profile photo overlap drawn on.
- Circle cropCrop one photo inside a circle and download the profile picture size for every network.
- Character counterCount a caption the way each network counts it, against every network’s limit at once.
- Image resizerCrop one photo to post, Story, cover and banner sizes across every major network at once.
Schedule your Bluesky posts
Posty publishes Bluesky posts at the time you set, with up to 4 images and a follow-up reply if you want one, alongside the other networks you run on one calendar.
Plans from $29 per workspace a month. Schedule Bluesky Posts