🗜️ Image Compressor
Batch compress JPG, PNG, and WebP images — your files never leave your browser
Drag & drop images here
or click to browse — JPG, PNG, WebP
How Image Compression Works
Image compression reduces file size by eliminating redundant data. Understanding the difference between lossy and lossless compression helps you choose the right quality setting for your needs.
Lossy vs Lossless Compression
Lossy compression (JPG, WebP in lossy mode) discards some visual data to achieve smaller files. The human eye is surprisingly bad at noticing subtle color changes, so clever algorithms remove data that's least perceptible:
- JPEG: Uses Discrete Cosine Transform (DCT) to convert 8×8 pixel blocks into frequency components, then discards high-frequency details based on the quality setting.
- WebP: Uses VP8 video codec technology with predictive coding to achieve ~25-35% smaller files than JPEG at the same visual quality.
PNG compression uses color quantization — merging similar colors so the DEFLATE algorithm can compress more efficiently. Transparency is fully preserved. This is the same approach used by TinyPNG.
Compression Ratio Formula
The compression ratio tells you how much space you saved:
For example, if a 1 MB image compresses to 300 KB, the compression ratio is (1 − 0.3/1.0) × 100% = 70%.
When to Use Each Quality Level
- 90-100%: Professional photography, print materials — nearly indistinguishable from original
- 70-89%: Web images, social media — excellent balance of quality and size
- 50-69%: Thumbnails, preview images — noticeable artifacts but acceptable for small displays
- 10-49%: Extreme compression — visible quality degradation, use only when file size is critical
Why Browser-Based Compression Matters
Traditional online compressors upload your images to a server, process them, and send them back. This means your images traverse the internet and may be stored on remote servers. This tool uses the Canvas API's toBlob() method to compress images entirely within your browser — zero data leaves your device.
Step-by-Step Guide
- Upload images — Drag and drop or click to select JPG, PNG, or WebP files. Multiple files supported.
- Adjust quality — Use the slider to set compression quality (10-100%). Lower values = smaller files but more quality loss.
- Preview results — See original and compressed file sizes, compression ratio, and visual preview for each image.
- Download — Download images individually, all at once, or as a ZIP file.
Frequently Asked Questions
No. All compression happens entirely in your browser using the Canvas API. Your images never leave your device — no server upload, no cloud processing, no storage.
JPG compression at 70-80% quality typically reduces file size by 40-60% with minimal visible quality loss. At 50% quality, you can expect 60-80% size reduction but with noticeable artifacts.
This tool uses color quantization to compress PNG — similar to TinyPNG. It merges similar colors to reduce file size while preserving transparency. At 75-100% quality, the difference is nearly invisible.
This tool supports JPG/JPEG, PNG, and WebP input formats. Compressed output is generated in the same format as the original, or you can choose a target format.