About Image Compressor

Image Compressor reduces the file size of JPEG, PNG, and WebP images using the browser-image-compression library. You control quality (10–100%), maximum output dimensions, maximum output file size in KB, and the output format — including conversion between JPEG, PNG, and WebP. A before-and-after preview and a savings percentage badge show exactly how much the compression achieved.

All compression runs locally in a Web Worker inside your browser — no image data is uploaded to any server. This makes it safe for compressing screenshots of confidential interfaces, personal photos, or any image you do not want to share with a third-party service.

Common Use Cases

Reducing hero image or product photo sizes before uploading to a CMS or e-commerce platform
Compressing screenshots and diagrams for use in documentation, Slack, or Notion without quality loss
Converting PNG assets to WebP for web delivery to take advantage of the format's superior compression ratio
Batch-preparing images to meet email attachment size limits or social media platform upload constraints

How to Use

Drop an image onto the drop zone or click to open the file picker (JPEG, PNG, or WebP, max 50 MB)
Adjust Quality, Max Width, Max Size, and Output Format in the Compression Options panel
Click "Compress" and wait for the Web Worker to process the image — a progress state is shown on the button
Review the compressed preview and savings badge, then click "Download" to save the result

Frequently Asked Questions

What quality setting should I use for web images?

For most web use cases, 70–80% quality strikes the best balance between visual fidelity and file size reduction. At 80%, JPEG compression typically removes 40–60% of file weight with no perceptible quality loss. For thumbnails or small UI images, 60–70% is usually acceptable. For print-quality output or images with fine text, stay above 85%.

Can I compress PNG files that have a transparent background?

Yes, but you must keep the output format set to PNG or WebP. If you convert a transparent PNG to JPEG, the transparency channel is lost and the background becomes solid (typically black or white). WebP is the recommended format for transparent images with strong compression — it supports an alpha channel like PNG but at significantly smaller file sizes.

Why does the Max Size setting sometimes not hit the exact target?

The browser-image-compression library attempts to reach the target size by progressively reducing quality and dimensions, but browser JPEG/PNG encoders are not deterministic — the same quality value can produce slightly different file sizes depending on image content. The tool will get as close as possible, but small overshoots of a few KB can occur with complex photographic images.