Free Custom Image Generator — Any Size, Any Format, Any Colour
Say goodbye to random placeholder APIs. Build precise, production-ready image mockups natively inside your browser. From ultra-compressed AVIFs to multi-layered ICO files, zero uploads are required. 100% Free.
Advanced Creative Controls
Modern Formats
We support WebP and AVIF generation right in your browser (if supported by your Canvas API), as well as standard PNG, JPEG, BMP, TIFF, SVG, and even clustered ICO files for favicons.
Limitless Backgrounds
Need a wireframe mockup? Use the text overlay tool. Need a generic avatar? Choose dynamic gradients or pure random noise functions to fill up your dimensions perfectly.
Frequently Asked Questions
Q: Which format provides the best quality-to-size ratio?
A: AVIF offers the highest compression ratios currently available in modern web browsers, often beating WebP by 20-30%. However, if you need universal frontend compatibility, WebP or JPEG are safer choices. For lossless transparency, use PNG.
Q: Can I generate multiple placeholder images at once?
A: Yes! Our Image Builder features a Generate Batch mode. Simply turn it on and we'll process up to 20 unique images simultaneously via Web Workers, zipping them directly on your hard drive.
Q: Is it safe to generate large 4K images?
A: Absolutely. Instead of freezing your browser, BlobForge detects large generation requests and offloads the heavy pixel processing to background Web Workers using `OffscreenCanvas`. This ensures a buttery smooth UI experience regardless of dimension sizes (up to 8000x8000px).