No. Compression runs entirely in your browser using the Canvas API. Your images are never sent to a server, stored in a database, or accessible to anyone outside your browser tab. This is especially important for photos that contain personal content, sensitive documents, or location data in EXIF.
For most web use, 75–85 is the right range. At 80, photos are typically 70–90% smaller than the original with no perceptible quality loss. Below 60, JPEG artefacts become visible — blocky edges, colour banding. Above 90, the file size saving shrinks quickly while quality barely improves. The tool shows you before-and-after sizes so you can tune the setting to your specific image.
WebP produces smaller files at the same visual quality — typically 25–35% smaller than JPEG at equivalent settings. Use WebP if the destination platform supports it (all modern browsers do; most CMSes now accept it). Use JPEG for older systems, email attachments, or when you need maximum compatibility. PNG input is converted to JPEG or WebP; neither format preserves PNG transparency.
PNG uses lossless compression — it doesn't discard pixel information. The resulting file is smaller than a raw bitmap, but larger than a lossy JPEG or WebP of the same image. If you want a significantly smaller file from a PNG, convert it to JPEG or WebP at 80–85 quality. The trade-off is that JPEG doesn't support transparency; if the PNG has a transparent background, you'll need to decide on a background colour before converting.
No enforced limit, but very large images (30+ megapixel photos) can cause the browser tab to use significant memory. If a tab crashes or becomes slow, try reducing the image dimensions before compressing. For typical smartphone photos (12–48 megapixels), the tool handles them without issues on most devices.
No, unless you explicitly set an output width or height. The compressor re-encodes at the original pixel dimensions by default. The file gets smaller because the codec uses fewer bits per pixel, not because there are fewer pixels. If you want to reduce dimensions, enable the resize option before downloading.
Yes. Drop multiple files and the tool compresses each one at the same quality setting. You can download them individually or as a single ZIP archive. The ZIP is assembled in your browser — no server involved.