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    Image Watermark Tool

    Image Compressor — Free Online Tool, 100% Local Processing

    100% local processing — your images never leave your browser.

    Upload Image

    Drag and drop an image here, or click to select

    Supports JPG, PNG and WebP

    Result

    Upload an image to see the before/after size comparison and preview.

    Features

    100% Local

    Your images never leave your browser. No server, no uploads, no size limits.

    Live Preview

    Drag the quality slider to instantly see the resulting size and quality.

    Multiple Formats

    JPG, PNG and WebP supported. Keep the original or convert — WebP is usually smaller.

    Why compress images?

    High-resolution photos are often several megabytes each, which slows down page loads, eats up storage and frequently exceeds the upload limits of forums, forms and email. Compressing an image dramatically reduces its file size while keeping acceptable quality, making sharing and uploading far smoother.

    100% local processing, private by design

    Unlike many online compressors that upload your images to a server, this tool runs entirely in your browser using the Canvas API. Your images are never uploaded, stored or sent to any third party — ideal for IDs, contracts and any photo containing personal information.

    Supported formats and tips

    JPG, PNG and WebP are supported. For photographs, JPG or WebP work best; keep PNG when you need transparency. In most cases a quality setting between 70–85% is visually indistinguishable from the original while saving a significant amount of space.

    Frequently asked questions

    Does compressing lose quality?

    Any lossy compression (JPG or WebP at less than 100%) discards some detail, but at 70-85% quality the difference is essentially invisible while file size drops dramatically. Lossless is only possible with PNG, which usually compresses less. For photos, 80% JPG or WebP is the standard sweet spot.

    Is there a file size limit?

    There is no fixed limit in the tool. Because compression runs on your own device rather than through a server, the practical limit is your device's memory — very large images work more comfortably on a laptop than on a phone.

    Which format compresses best?

    WebP typically produces the smallest file at the same visual quality — around 25-35% smaller than JPG. JPG is the safest choice for maximum compatibility (email, older devices, printers). PNG is only smaller when the image has large flat areas of colour, like screenshots.

    Is my image uploaded to a server?

    No. ImageMarker uses the browser's Canvas API to compress locally, so your photo never leaves your device. This matters for images containing personal information like IDs, contracts, or medical scans.

    Can I compress a batch of images?

    Not yet — the compressor handles one image at a time with a live quality slider. For a folder of photos, compress them one after another; each takes only a moment because nothing is uploaded.

    What's a good quality setting?

    80% is the default for a reason — for photographs it looks identical to the original at roughly one-third the size. Drop to 65-70% for backgrounds or thumbnails, push to 85-90% for hero images or portrait detail.

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