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Test Image Generator — Any Ratio, Size & Quality

Generate test images at any aspect ratio, resolution, pattern, quality or exact file size.

A test image generator creates images at whatever aspect ratio, resolution, pattern and quality you need — 16:9, 1:1, 9:16, Open Graph 1.91:1 or a custom size — as PNG, BMP, GIF, JPEG or WebP. Use them to check responsive layouts, upload limits, thumbnail cropping and compression behaviour.

Runs in your browser
Ratios
11 presets from 1:1 to 21:9, plus A4 portrait and landscape and fully custom dimensions
Resolution
Up to 12,000 px on the longest edge, capped at 40 megapixels
Patterns
Solid, linear and radial gradients, checkerboard, grid, stripes, colour bars, mesh and noise
Exact sizing
PNG output can be padded to a precise byte count via a metadata block
Privacy
Runs entirely in your browser — nothing is uploaded
Cost
Free, unlimited, no sign-up

Frequently asked questions

Why would I want noise instead of a gradient?

Noise is effectively incompressible, so it is the worst case for a compression or bandwidth test. A gradient compresses extremely well and gives you the opposite extreme with the same dimensions.

How do I get a file of an exact size?

Choose PNG and enable "Pad to an exact file size". The generator appends a metadata block sized to make up the difference, which leaves the image itself untouched.

What are the colour bars for?

They are a test card. Because the eight bars have known values, they make it obvious at a glance if a pipeline has shifted colours, swapped channels or clipped the range.

How to use the sample image generator

  1. 1Choose the aspect ratio.
  2. 2Set the longest edge.
  3. 3Set the width.
  4. 4Set the height.
  5. 5Choose the pattern.
  6. 6Pick the primary colour.
  7. 7Pick the secondary colour.
  8. 8Set the pattern scale.
  9. 9Choose the format.
  10. 10Set the quality.
  11. 11Turn "Pad to an exact file size" on or off as needed.
  12. 12Set the target file size.
  13. 13Choose the unit.
  14. 14Set the how many images.
  15. 15Enter or paste your seed.
  16. 16Press Run, then download the result when it is ready.

Embed this tool

Put the working sample image generator on your own site. It runs in your visitors' browsers exactly as it does here — free, no account, nothing uploaded.

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