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Utility

Online Image Compressor - Local Batch JPG PNG WebP Tool

Runs locally · no upload

Compress JPG, PNG and WebP images locally in your browser with batch upload, quality slider, format conversion and zip download. No server upload, fully private.

Overview

Compress JPG, PNG and WebP images in batch directly in your browser. Tune quality and max width, and convert between JPG, PNG and WebP on demand. All decoding, scaling and encoding happen in a Canvas - your files never leave the device. Ideal for private photos, product shots and social-media assets. Up to 20 files per batch, 20 MB each.

How to use

  1. Click "Choose files" and select up to 20 JPG / PNG / WebP images
  2. Drag the quality slider (70-80% is usually a good balance)
  3. To resize, set a "Max width" in pixels (0 keeps the original)
  4. Pick an output format (WebP is usually 25-35% smaller than JPG)
  5. Click "Compress", watch the progress bar, then download each file

Formula

compressionRatio = (1 - compressedSize / originalSize) × 100%; savedBytes = originalSize - compressedSize; scaledWidth = min(originalWidth, maxWidth) and scaledHeight = originalHeight × scaledWidth / originalWidth.

Common scenarios

Blog cover images

Upload four 6 MB raw camera shots, set quality 75%, max width 1280 px and WebP output - each lands at 200-400 KB and the page loads dramatically faster.

E-commerce product photos

Convert a set of 2 MB PNG product shots to JPG at quality 85. Transparent backgrounds auto-fill to white and each image drops to ~400 KB, halving above-the-fold weight.

Social avatar shrink

Export an 8 MB iPhone HEIC to JPG from your photo library first, then compress here at quality 80 with 720 px max width. The result passes most apps' avatar upload limits.

FAQ

Will my images be uploaded to a server? Is it private?

No. Processing happens entirely in your browser. Files are read into memory via FileReader and re-encoded with Canvas - there is no fetch or XHR upload at any point. Everything clears from memory when you close the tab.

Will quality drop visibly? How do I choose a quality level?

Above 90 the difference is invisible; 70-85 is the sweet spot for size vs. quality with no visible loss; below 60 you may see blocking and fuzzy text. Use 80-90 for photography, 70-80 for general content, 60-70 for thumbnails.

Which formats are supported? How much smaller is WebP vs. PNG?

JPG, PNG and WebP can be converted in any direction. For the same image WebP is typically 25-35% smaller than JPG and 50-80% smaller than PNG; transparency is preserved when converting PNG to WebP, while still cutting size roughly in half.

Are there any batch or size limits?

Up to 20 files per batch and 20 MB per file - this prevents the browser from exhausting memory and crashing. For more files or larger ones, split into batches. Processing is sequential and the progress bar reflects current completion.

Why did some images grow larger after compression?

Tiny files (< 10 KB) or already-highly-compressed JPG / WebP can grow because of encoder overhead. The tool detects this and keeps the original byte count (savedBytes shown as 0); you still get the processed file, but no fake savings are reported.

Will the compressed file keep EXIF metadata?

No. Canvas re-encoding drops EXIF (GPS, camera model, capture time) by design, which neatly strips sensitive metadata. If you need EXIF retained, use your OS photo app or a dedicated metadata tool instead.

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