The Hidden Cost of Free Online Image Compressors

I analyzed what happens when you upload a photo to 5 popular free image compression sites. The Test I uploaded a 4.2MB photo to each service and monitored network requests. Results: Service A : File sent to their CDN (AWS us-east-1). 12 analytics trackers fired simultaneously. Service B : File uploaded, but 5 minutes later a second request sent the file to a different domain. Service C : Cleanest of the five, but their privacy policy reserves the right to "use uploaded content to improve compression algorithms." Service D : 23 third-party scripts loaded on the page. Your image URL is accessible to all of them. Service E : Actually clean — only one request to their server for processing. Only one of five didn't leak data to third parties. One. The Alternative I built compress2png.com to test whether image compression could work without any server. Turns out Canvas API + clever JavaScript handles it: Resize images client-side before export Strip EXIF/metadata in the browser Convert to optimal formats based on content For format-specific needs, svg2png.org handles vector conversion and webp2png.io handles next-gen format conversion — all browser-local. Check the Network tab next time you use a "free" online tool. You might be surprised what you find.