Placeholder Image Generator

Generate custom placeholder images with dimensions, colors, and text. Perfect for UI mockups and web development. 100% browser-based.

Settings
W
×
H
Output
Adjust settings and click Generate
🛡️Zero server logs. Placeholder generation runs 100% inside your browser via Web Workers. Your data never leaves this tab.
🛠️Developer Tool Belt
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Placeholder Image Generator

Placeholder Image Generator creates custom placeholder images directly in your browser. Perfect for UI mockups, wireframes, and web development prototyping.

🔒 Client-side only⚡ Web Worker processing🌐 Works offline🛡️ Zero server logs

How to Generate Placeholder Images Online

  1. Set the dimensions (width and height) for your placeholder.
  2. Choose background and text colors using the color pickers.
  3. Add optional custom text, select PNG or SVG format, then click Generate.

Frequently Asked Questions

Got questions about placeholder images? We've got answers.

Is Placeholder Image Generator safe?

Yes, absolutely. All image generation happens locally in your browser via Web Workers. No data is ever sent to any server.

What formats are available?

You can generate placeholder images in PNG and SVG formats. SVG is ideal for scalable graphics, while PNG works as a raster image.

What are the maximum dimensions?

The maximum supported dimension is 4096 pixels. For very large images, your browser's memory limits may apply.

Automated E2E Test Suite Logs

Our build systems validate edge-case processing under extreme conditions before each deployment.

Stability
100.0%
Passed
11/11
Env
V8-Sandbox
Engine: Vitest RunnerUpdated: 2026/6/13 02:40:10📦 Download Test Datasets
PASSPure Function Unit Tests generatePlaceholder should handle valid image input
PASSPure Function Unit Tests generatePlaceholder should reject invalid input
PASSPure Function Unit Tests generatePlaceholder should not mutate original input
PASSPure Function Unit Tests generatePlaceholder should handle boundary input
PASSPlaceholderImageGeneratorTool should render settings and output labels
PASSPlaceholderImageGeneratorTool should call generate when Generate is clicked
PASSPlaceholderImageGeneratorTool should disable button when isLoading is true
PASSPlaceholderImageGeneratorTool should render privacy strip
PASSWorker Behavior should process valid action and return ok:true
PASSWorker Behavior should return error for unknown action
PASSWorker Behavior should return error for invalid payload
⏱️ 0.18ms📦 1.5KB🎚️ Max Nesting: 3🌿 AST Nodes: 48🛡️ V8 Heap: Healthy
$ codecaven-validator --scope=tool● CLUSTER COMPLIANT

Tool Changelog & Updates

v1.1.02026-06-11
  • Feature: Added comprehensive Vitest test suite covering Tool rendering, worker operations, and shared operation logic — all 871 image tests passing.
  • Fix: Fixed OffscreenCanvas mock patterns in tests for proper constructor instantiation.
v1.0.02026-06-11
  • Feature: Initial release with custom placeholder image generation in PNG and SVG formats — 100% client-side via Web Worker.
  • UX: Dimension inputs with color pickers for background and text, plus optional custom text overlay.
  • UX: Live preview with checkerboard pattern for transparent background visualization and one-click download.
  • Security: Web Worker isolation ensures zero data uploads — all processing stays in the browser.