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Mastodon image sizes and free resizer

Turn one photo into every Mastodon size in seconds. Pick what must stay in the crop, then download one file or all of them.

  • Never uploaded
  • Sizes from each network's own help pages
  • Every size in one ZIP
1Your photo

Your photo is resized inside your browser. It is never uploaded to our servers.

2Pick the sizes
3 selected
Mastodon
Instagram
Facebook
LinkedIn
X
YouTube
Pinterest
Threads
Google Business
Bluesky
3

Download

Add a photo to see every size you picked here.

Mastodon image size guide

Each size comes from the network's own help or spec pages, linked under its table, with the date we last checked it.

Mastodon image sizes

Sizes that fit the network's limits

Mastodon publishes limits rather than one size: images above 8.3 megapixels (3840 × 2160) are scaled down, and each server can set its own file limit. These sizes stay under the megapixel limit.

FormatPixelsShape
Landscape postA wide image in a post (16:9)1920 × 108016:9
Square postA square image in a post (1:1)1440 × 14401:1
Portrait postA tall image in a post (4:5)1440 × 18004:5

Largest image Social Publish sends to Mastodon: 8.0 MB.

Checked 24 Oct 2026:Mastodon docs: posting
Other networks:InstagramFacebookLinkedInXYouTubePinterestThreadsGoogle BusinessBlueskyAll networks

Questions

Is my photo uploaded anywhere?

No. The photo is read and resized by your own browser, and the files you download are made on your device. Only the list of sizes comes from our server.

Where do these sizes come from?

From each network's own help or specification pages, linked under every table with the date we last checked them. Where a network publishes only limits (such as a width range), the sizes are marked as fitting those limits rather than recommended by the network.

What is the difference between "Fill & crop" and "Fit whole photo"?

Fill & crop covers the whole size with your photo and trims what does not fit, keeping the point you clicked in view. Fit whole photo keeps every part of the photo and fills the empty space with a border colour you choose.

Is it free? Do I need an account?

It is free, with no account, no limit on photos and no watermark.

Resize once, post everywhere

Social Publish checks every photo against each network before it posts, then publishes or schedules it to all your networks in one click.

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