How to Compress Images Privately in Your Browser

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When you need to send photos, upload receipts, or optimize assets for a website, image file sizes can quickly become an obstacle. Many online tools offer to compress your images for free, but they come with a catch: your files are uploaded to their remote servers.

For personal photos, confidential business documents, or identity verification scans, uploading your files to third-party databases is a significant security risk.

To solve this, ScanApp has launched a new 100% private batch image compressor that runs entirely locally inside your web browser.

Why Local Compression Matters

Traditional image compressors work by uploading your file to a cloud server, running a compression script on their hardware, and sending you a download link. This approach has several downsides:

  • Privacy Exposure: Your files could be cached, saved, or inspected on remote servers.
  • Upload Latency: If you have a slow internet connection or very large photos, waiting for uploads can take minutes.
  • Bandwidth Usage: Uploading and downloading megabytes of files consumes mobile data.

ScanApp’s local compression bypasses the cloud entirely. Using standard browser APIs (HTML5 Canvas), the compression script runs in your browser using your device’s own CPU. Your files never leave your computer or phone.

How to Use ScanApp Image Compressor

Our new interface is inspired by premium batch utilities, enabling you to optimize up to 100 images in a single batch.

  1. Open the ScanApp Image Compressor.
  2. Add your files: Drag and drop your images into the designated dashed upload box, or click the area to select files from your file manager. You can also paste screenshots directly from your clipboard using Ctrl+V or Cmd+V.
  3. Choose quality settings: Adjust the Quality slider (we recommend 70% to 80% for the perfect balance of visual quality and file size savings).
  4. Configure advanced settings (optional):
    • Set a Maximum width to scale large photos proportionally.
    • Choose a target Output format (Smart, JPG, WebP, PNG, AVIF, GIF, or BMP). Smart mode automatically compresses transparent PNGs to WebP and others to JPG.
  5. Download: Click Download on individual file rows, or click Download all (ZIP) to bundle all optimized files into a single, offline ZIP package.

Frequently Asked Questions

Which formats can I compress?

You can load and process JPG, PNG, WebP, AVIF, GIF, BMP, and SVG images. For output formats, you can choose to convert your output to JPEG, WebP, PNG, AVIF, GIF, or BMP.

How much space will I save?

Most standard JPEGs and PNGs compress by 50% to 80% without any noticeable loss in visual quality.

Is there a file size limit?

You can upload individual files up to 50 MB each. The batch processor can handle up to 100 files simultaneously.

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