UFOZoo

Image Compressor — Reduce JPG, PNG, WebP File Size

Reduce image file sizes with quality adjustment and live preview. Compare original vs compressed side by side. Supports JPG, PNG, and WebP. Browser-based.

Features

  • ✓Compress JPG, PNG, and WebP images with adjustable quality slider
  • ✓Interactive before/after comparison slider — drag to reveal differences
  • ✓Batch compression — open and compress multiple images at once
  • ✓Quality presets for quick optimization: Smallest, Web, Balanced, High
  • ✓Real-time file size comparison bar showing exact savings
  • ✓Save individual images or batch save as ZIP
  • ✓Paste from clipboard (Ctrl+V) for instant compression
  • ✓All compression happens in your browser — no server uploads
  • ✓100% free with no file size limits

How to Use

  1. 1Open images by clicking the drop area, dragging files, or pasting from clipboard (Ctrl+V).
  2. 2Choose an output format (JPEG, PNG, or WebP) from the sidebar.
  3. 3Use quality presets for quick optimization, or fine-tune with the slider.
  4. 4Drag the before/after comparison slider to inspect compression differences at full resolution.
  5. 5Review file size savings shown in the real-time comparison bar.
  6. 6Click Save to save individual images, or Save All to save as ZIP.
  7. 7How to compress an image for email attachment: open the image, set quality to 60–70% for maximum compression, select JPEG format for photos. The real-time size bar shows if the result fits your email's attachment limit before saving.
  8. 8How to find the best quality-size balance: open your image, start at 80% quality and use the before/after slider to compare. Gradually lower quality in 5% steps until you find the point where file size is acceptable but quality still looks good to your eyes.
  9. 9How to batch compress images for a website gallery: open all your gallery images at once, set quality to 80% for WebP output, verify a few images with the comparison slider, then click Save All to get the entire optimized gallery as a ZIP file.

Frequently Asked Questions

How much can I compress an image?

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The amount of compression depends on the image content and format. For JPEG and WebP, lower quality settings produce smaller files. A quality setting of 60–80% typically reduces file size by 40–80% with minimal visual loss. PNG compression is limited since PNG is already a lossless format.

What's the difference between JPEG and WebP compression?

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WebP generally provides 25–35% better compression than JPEG at the same visual quality level. For web use, WebP is recommended. JPEG is more universally supported. PNG is best when you need lossless quality, but file sizes will be larger.

Does compression reduce image dimensions?

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No. This tool only adjusts the compression quality, not the image dimensions. The output image has the same width and height as the original. Use the Image Resizer tool if you need to change dimensions.

What quality setting should I use for web images?

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For JPEG and WebP, 80–90% is recommended for high-quality images where file size still matters. For maximum compression, 50–60% can work well for photos with less detail. Use the before/after slider to compare and find the sweet spot for your specific images.

Can I compress images in batches?

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Yes. Open multiple images at once — they all appear in the list. You can compress them with the same quality setting and output format. Save them individually or click Save All to get a ZIP archive of all compressed images.

Does compression support transparency?

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PNG and WebP formats support transparency. Compressing a PNG with transparency preserves the alpha channel. JPEG does not support transparency — transparent areas will be filled with white when converting to JPEG output.

Is there a limit on file size?

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Since all processing happens in your browser, the practical limit depends on your device's available memory. Most images under 50MB work fine. Very large images (100MB+) may cause performance issues on lower-end devices.

Is my image uploaded to a server?

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No. All image compression happens entirely in your browser using the HTML5 Canvas API. Your image is never uploaded, stored, or transmitted anywhere.

What's the best output format for web images?

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WebP is generally the best choice for web images because it offers superior compression with transparency support. JPEG is good for photos without transparency needs. PNG is best when you need lossless quality, such as for screenshots with text or UI elements.

Can I compress SVG files?

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No. This tool works with raster image formats (JPEG, PNG, WebP) that use pixel-based compression. SVG is a vector format with a different compression approach. For SVG optimization, look for a dedicated SVG minifier tool.

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