Detect Image MIME Type & File Format

Detect true binary image container formats, verify file extensions against magic bytes, and check alpha channels.

How It Works & Processing Standards

Detect true binary image container formats, verify file extensions against magic bytes, and check alpha channels.

Your input data is never sent to any server and is securely processed on your device.

Current Limits

  • Desktop max file size: 40MB
  • Mobile max file size: 20MB

Detect Image MIME Type & File Format is a 100% free, browser-based online utility. All calculations and file conversions run locally inside your browser (Local-First) without sending data to remote servers, keeping your documents and inputs strictly private.

How to Use Detect Image MIME Type & File Format

  1. 1
    Select FileDrop any image file into the tool.
  2. 2
    Review AnalysisView actual MIME format, extension match status, and alpha presence.

Common Use Cases

  • Diagnosing why an image with a .jpg extension fails to open (detecting disguised WebP files)
  • Verifying if PNG graphics genuinely contain transparent alpha channels
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