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Mastodon Image Size Checker — Free Tool

Check if your images meet Mastodon's size requirements. Preview profile photos, headers, and post images.

Required dimensions
Width
400px
Height
400px
Ratio
1:1
Max 2 MB
Click or drop an image here
JPG, PNG, WebP
Preview — Profile Photo (1:1)
Upload an image to preview

Features

  • Check image against required dimensions
  • Drag to reposition crop preview
  • All Mastodon image sizes in one place
  • Pass/fail checks for width, height, ratio, file size

Image types supported

  • Profile
  • Header
  • Post

How to use this tool

  1. Select the image type from the dropdown (profile photo, cover, post, etc.).
  2. See the required dimensions, aspect ratio, and any file size limits.
  3. Upload your image by clicking or dragging it into the upload area.
  4. Check the pass/fail results for width, height, aspect ratio, and file size.
  5. Drag the image in the preview to reposition it within the crop frame.
  6. Use the reference table on the right to quickly switch between image types.
  7. Ready to publish? Create a free BulkPublish account to schedule and publish across all platforms.