The short version
When you pick an image in IMGifyx, your browser reads the file directly from disk into memory using the File API. From there, every operation — resizing, compressing, converting, cropping — runs in JavaScript on your own machine. The result is handed back to you as a download. At no point does the original or the result leave your device.
What's actually doing the work
Three browser technologies handle the heavy lifting. The Canvas API draws and re-renders pixels for resizing, cropping and filters. Web Workers run compression and batch jobs on a background thread so the page stays responsive. And libraries like browser-image-compression run as ordinary client-side code — they ship to your browser and execute there, the same as any web page's scripts.
- Canvas API — pixel-level redraw for resize, crop, rotate, watermark and filters.
- Web Workers — off-main-thread processing so large batches don't freeze the UI.
- File & Blob APIs — read your selection and package the output for download.
How to verify it yourself
If you're technically inclined, open your browser's developer tools, switch to the Network tab, and run any tool. You'll see the page assets load once, then silence — no upload request fires when you process an image. You can even disconnect from the internet after the page loads and the tools keep working.