Every size in one place. Checked October 2026.
Quick reference
| X | Bluesky | Mastodon | ||
|---|---|---|---|---|
| Profile picture | 400 × 400 | 1000 × 1000 | 400 × 400 | 400 × 400 |
| Banner / header | 1500 × 500 | 3000 × 1000 | 1500 × 500 | 1584 × 396 |
| Post image | 1600 × 900 | 1600 × 900 | 1600 × 900 | 1200 × 627 |
| Images per post | 4 | 4 | 4 | up to 20 |
| Image file size | 5 MB | 2 MB | 16 MB | not stated |
Sizes in pixels. Post image is a safe landscape default; square (1080 × 1080) and portrait (1080 × 1350) work on all four.
X (Twitter) image size
- Profile picture: 400 × 400, shown as a circle. Under 2 MB.
- Header: 1500 × 500 (3:1). The profile picture covers the lower left on desktop.
- Post images: up to 4, 5 MB each. JPEG, PNG or WebP.
- GIF: one per post, up to 15 MB.
- Alt text: up to 1,000 characters.
Single 16:9 and square images show uncropped. Two to four images get cropped into a grid, so keep the subject centered. Preview on a phone.
Scheduling on X: schedule a tweet.
Bluesky image sizes
- Profile picture: 1000 × 1000, shown as a circle. PNG or JPEG, up to 1 MB.
- Banner: 3000 × 1000 (3:1). PNG or JPEG, up to 1 MB.
- Post images: up to 4, 2 MB each (formerly 1 MB).
- GIFs: play as looping video.
Bluesky banner size
3000 × 1000, a 3:1 strip. Your profile picture overlaps the lower left on desktop and mobile. Keep text and logos in the upper right.
Bluesky profile picture size
1000 × 1000, square. The circle mask clips the corners; leave some padding around faces and logos.
Bluesky keeps a single image's own aspect ratio in the feed.
Mastodon image sizes
Defaults on a stock server. Your server can change them.
- Profile picture: downscaled to 400 × 400. Up to 2 MB.
- Header: downscaled to 1500 × 500. Up to 2 MB.
- Post images: up to 4, 16 MB each. PNG, JPEG, WebP, HEIF or AVIF.
- Large images are downscaled to 8.3 megapixels (3840 × 2160).
- Animated GIFs: one per post, converted to silent MP4.
- Alt text: up to 1,500 characters, and expected. Some people filter out posts without it.
Set a focal point when you upload. Mastodon uses it to crop the preview.
More: schedule Mastodon posts.
LinkedIn image sizes
- Profile photo: 400 × 400 or larger. PNG or JPG, up to 8 MB.
- Background photo: 1584 × 396 (4:1). PNG or JPG, up to 8 MB.
- Post images: 1200 × 627 landscape, 1080 × 1080 square, 1080 × 1350 portrait.
Portrait takes the most room in the feed.
Image formats
| Format | Use for |
|---|---|
| JPEG | Photos and painted art |
| PNG | Screenshots, text, flat colors, line art |
| WebP | Either, smaller files (not on LinkedIn) |
| GIF | Short loops |
Export in sRGB. Other color profiles can look washed out after upload.
One image for every platform
- Landscape: 1600 × 900.
- Square: 1080 × 1080.
- Under 2 MB, so Bluesky takes it too.
- Subject in the center, so grids and circles don't cut it.
On a Mac, Preview resizes in bulk: select the images, Tools → Adjust Size, set the width, export.
Post it with Statuz
A free CLI for X, Bluesky, Mastodon and LinkedIn. Add the image once, with alt text:
statuz media add --path ./launch.png --alt "Dashboard with weekly signups up 12%"
statuz posts create --text "v2 is out" --media <media id> --to x --to bluesky --to mastodon --to linkedin --at "tue 9am"Statuz checks the file against every destination's limit before saving, so a 3 MB PNG fails on Bluesky now, not at post time. On your computer it doesn't resize for you; Statuz Cloud shrinks an image to fit each platform as it goes out, the original untouched. Install, Scheduling.
Common mistakes
- Uploading straight from the camera. Resize first.
- Text near the edges of a header.
- Faces at the edge of a multi-image post.
- No alt text on Mastodon.
- Bluesky banners and profile pictures over 1 MB.
More: cross-posting, best time to post art.