About ImageZap
An independent tool to prepare fast web images without sacrificing quality or privacy.
Why it exists
Images are usually the heaviest resource on a web page and the most common cause of a poor Largest Contentful Paint (LCP). Optimizing them well isn't hard, but the usual process is tedious: export from an editor, run the files through an online compressor that limits how many you can upload, repeat for every format and write the <picture> markup by hand.
ImageZap brings that whole workflow into a single screen. It's built for designers and developers who want control —per-format quality, chroma subsampling, responsive variants— without giving up the convenience of drag and drop.
How it works
ImageZap is a static web application. When you convert an image:
- The browser decodes the original file (or, if it can't, a WebAssembly decoder does).
- If you asked for it, the image is resized with a high-quality Lanczos filter in linear color space.
- It's encoded with the matching codec compiled to WebAssembly: libavif for AVIF, libwebp for WebP, libjxl for JPEG XL, MozJPEG for JPEG and OxiPNG for PNG. These are the same codecs used by Squoosh, the open-source project from the Chrome team.
- Everything runs in Web Workers spread across your CPU cores, so the interface stays responsive.
Your images are never sent to a server. Originals are kept in your browser so you can convert them again without re-uploading, and you can delete them at any time.
Who is behind it
ImageZap is a personal project by Enrique Alonso Delgado, a web developer focused on performance. The guides on this site collect what I apply on real projects: which format to choose, how to write srcset and sizes correctly and how to prioritize the main image to improve Core Web Vitals.
You can reach me through the contact page or on LinkedIn.
How it's funded
ImageZap is free and has no paid plans. To cover hosting and development costs, the site shows a small number of Google AdSense ads on content pages, always clearly separated from the tool and respecting your consent choices. See the privacy policy and cookie policy for details.
Principles
- Privacy by design: no file ever leaves your device.
- No artificial limits: no daily quotas, no watermarks.
- Technical honesty: we show the real size of every result; if a conversion makes the original worse, you'll see it (and can keep the original).
- Useful content: guides are written and reviewed by hand, with a visible update date.