Mastodon Post Image Size (2026)
Post images display best at 1280×720 px (16:9). Up to 4 attachments per post; previews crop toward 16:9.
| Placement | Pixels | Ratio | |
|---|---|---|---|
| Landscape (recommended) — 16:9 Matches the feed preview crop |
1280×720 | 16:9 | |
| Square — 1:1 Works for single images |
1200×1200 | 1:1 | |
| Max attachments Arranged in a grid |
4 images | — |
Use 1280×720 for feed images
Mastodon previews images toward a wide 16:9 crop in the timeline. Uploading 1280×720 px matches that preview so your image is not awkwardly cut. Full images open when tapped.
Multiple images
You can attach up to 4 images per post; they display in a grid, so use consistent ratios for a tidy layout.
Format and quality
Upload PNG or JPG. Start high-resolution — Mastodon downscales large images on its own.
FAQ
What is the best Mastodon post image size in 2026?
1280×720 px (16:9) matches the timeline preview crop; 1200×1200 px (1:1) also works for single images.
How many images can a Mastodon post have?
Up to 4 images per post, shown in a grid.
What aspect ratio does Mastodon crop post previews to?
Previews lean toward 16:9, so a 1280×720 landscape image fits cleanly.