Generate test images for QA and pipeline testing

Procedurally-generated test images for upload-flow tests, image-pipeline QA and viewer compatibility checks. Seven patterns (SMPTE bars, grayscale steps, RGB gradient, checker, line grid, concentric circles, solid colour) render to Canvas and export as PNG, JPEG or WebP — pick resolution from 640×480 to 4K and quality 0–100 for lossy formats.

How to use

Pick a pattern from the dropdown — preview updates instantly.

Pick resolution and output format (PNG / JPEG / WebP).

Adjust quality for JPEG/WebP and hit Download.

Colour bars, grayscale, gradients and grids — PNG, JPEG, WebP up to 4K

Pattern

Resolution

Format

Quality (0–100)

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Features

Seven patterns — SMPTE bars, grayscale wedge, gradient, checker, grid, circles, solid Five resolutions — 640×480, 720p, 1080p, 1440p, 4K PNG (lossless), JPEG and WebP with quality 0–100 — same canvas, three exports Resolution badge baked into the image — visible identifier even after pipeline resize

Frequently Asked Questions

When should I use which format?

PNG — for upload-flow tests where pixel-exact bytes matter, or for testing transparent-PNG support. JPEG — for testing photo-pipeline behaviour and quality-vs-size tradeoffs. WebP — when you specifically need to test WebP decoder support; not all older browsers / image viewers can open it.

Why does the checker pattern look slightly off at 4K?

The checker square size scales with image width to stay visually consistent, but at very high resolutions it rounds to the nearest integer pixel — slight banding is normal and intentional. If you need exact 1:1 pixel-aligned checker for a calibration target, generate at the actual target resolution rather than rescaling.

Can I add EXIF metadata?

Not currently — canvas.toBlob does not emit EXIF. For EXIF-bearing test images use a dedicated EXIF editor or shoot real photos with a controlled camera. The patterns here are for pipeline / viewer / upload testing where metadata is not the focus.

Why is the resolution badge baked into the image?

So downstream pipelines (CDNs, resize services, viewers) that silently downscale your image still show you what the original was. If the badge reads 1920×1080 but the file you receive is 1280×720, you know exactly where the resize happened.

💡 Want us to improve this tool just for you?

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Published 21 May 2026