What “without uploading” means
A local workflow reads the image through the browser and performs image processing on the device instead of sending the selected image to a remote media-processing API. This can avoid a file upload to that processor, but it is not a general security guarantee about the website, browser, extensions, or device.
If the image is highly sensitive, consider whether you need an online website at all. A locally installed application that you trust and can run offline may be a better fit for your requirements.
Compress an image with Pixuna
Open Pixuna’s Image Compressor and select an image. The file is processed in the browser using image decoding and a canvas, then you can review and download the result.
The current compressor scales images wider than 1,200 pixels down to that width and encodes JPEG at a fixed quality. It has no target-size control or quality slider. JPEG is lossy and does not preserve transparency, so keep the original and inspect the result.
Know the local-processing limits
Browser processing consumes device memory and compute. Large images may take longer, fail to decode, or exceed resources available to a particular browser. Output encoding support also varies, which is why the compressor uses JPEG rather than offering a wide format menu.
A local compressor cannot promise an exact file size or identical visual quality for every image. If the output is too large, dimensions and encoding choices affect the result, but the current Pixuna compressor does not offer a target-size loop.