“Online” does not tell you where an image is processed
An online tool can run image code in your browser or upload the selected file to a server. A website may also use different paths for different tools. Do not infer where a file goes from the words “online,” “private,” or “secure”; inspect the tool’s explanation and network behavior.
Browser-side processing can avoid sending the image to the application’s processing API, but it still relies on a website and its scripts. Use a service you trust, keep your browser updated, and avoid uploading highly sensitive images when you cannot establish how they are handled.
Check the service before choosing a file
Look for a clear explanation of local versus server processing, what happens after an upload, how temporary output files are handled, whether a third-party processor is used, and what logs or backups may retain. A statement that a file is deleted after processing should say which storage it covers and how that claim is implemented.
A privacy policy may distinguish file content from account, analytics, or operational data. Read the relevant sections and look for a date or a way to contact the service. If the policy does not explain a detail you need, treat it as unknown rather than assuming a favorable answer.
How Pixuna’s image compressor works
Pixuna’s image compressor loads the selected file in the browser and uses an image element and canvas to resize and encode it. It scales images wider than 1,200 pixels and exports JPEG at a fixed quality setting.
This is not a claim that every part of a website runs locally or that browser processing is a security certification. It describes the image-processing path implemented in the repository.
Use the tool and review its output
Open the Image Compressor, choose an image, start processing, then compare the result before downloading. The output is JPEG, so transparent areas will not be preserved; the image can also be resized and lossy compression can change detail. Keep the original if that matters.
For a highly confidential image, consider an offline desktop application or a local workflow you can independently inspect. For ordinary images, choose a service whose processing and retention explanation meets your needs.