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 uplo...