Mastodon Image Sizes & Presets

Mastodon avatars should be 400x400 pixels. Supported formats include PNG, JPEG, and GIF (including animated). The maximum file size is typically 2 MB, though this can vary by instance. The avatar is displayed as a circle.

Mastodon headers should be 1500x500 pixels (3:1 aspect ratio). This matches the same dimensions as X/Twitter headers. PNG, JPEG, and GIF formats are supported up to 2 MB on most instances.

Yes. Most Mastodon instances support animated GIF avatars and headers. However, some instances disable animation by default to reduce bandwidth. Users can toggle animation display in their preferences.

No. Mastodon is decentralized, so each instance can set its own limits. The default settings use 2 MB for avatars and headers, and 10 MB for media attachments, but individual instance admins can adjust these.