Image Compressor
Reduce image file size to improve website loading speed and save storage space.
Drag image here or click to select
PNG, JPG, WEBP (max 10MB)
Original
Compressed
What is Image Compression?
Image compression is a technique to reduce image file size, improving website loading speed and saving storage space. Use the quality slider to find the perfect balance between image quality and file size, and compare the original and compressed results side by side. All processing happens in your browser, ensuring complete privacy.
User Guide
- Drag and drop or click to upload an image file
- Select desired quality (10~100%) using the slider
- Click the Compress button to run compression
- Compare the original and compressed file sizes
- Download the compressed image if the result is satisfactory
Supported Formats
- PNG: Supports transparency, lossless compression
- JPG/JPEG: Best for photos, lossy compression with high compression ratio
- WEBP: Modern format with excellent compression efficiency
Core Features
- Precise compression control with a 10%-100% quality slider
- Side-by-side file size comparison of original and compressed images
- Real-time calculation of compression ratio (size reduction)
- Support for PNG, JPG, and WebP formats
- Browser-based processing with no server uploads for complete privacy
When This Comes in Handy
- Optimizing image loading speed for websites
- Reducing image file sizes for email attachments
- Managing product image sizes for blogs or online stores
- Shrinking photo file sizes before uploading to social media
- Batch compressing photos to save cloud storage space
Common Questions
Q: Is my image uploaded to a server?
No, all processing is done in your browser. Your images are never uploaded to any server, ensuring complete privacy.
Q: What is the optimal quality value?
Generally, 70-85% provides a good balance between file size and quality. Adjust based on your specific needs.
Q: Can PNG images be compressed?
PNG is a lossless format, so compression effect is limited. For higher compression, consider converting to JPG or WebP.
Q: Will the image quality be noticeably worse after compression?
At 70% quality or above, the difference is typically imperceptible to the human eye. Preview the result before downloading to find your preferred balance.
Q: Can I compress multiple images at once?
Currently, one image can be processed at a time. Upload and compress each image individually.
Q: Does compression modify my original file?
No, the original file is never modified. A new compressed file is created separately for download.
Q: Does compression reduce the image resolution?
No, image compression only reduces file size. The resolution (width x height in pixels) remains the same. Use the Image Resizer tool to change dimensions.
Q: What is WebP format?
WebP is a modern image format developed by Google that provides smaller file sizes than JPG and PNG while maintaining good quality. It is supported by most modern browsers.
Q: Is transparency preserved after compression?
Transparency is preserved in PNG and WebP formats. JPG does not support transparency, so transparent areas will be filled with white.
Q: Does it work on mobile devices?
Yes, it works on mobile browsers. You can select images from your gallery to compress on your phone or tablet.
How It Works
The image compressor uses Canvas API to re-encode images. For JPEG, canvas.toBlob("image/jpeg", quality) adjusts compression via the quality parameter (0-1). Lower quality removes more high-frequency components during DCT (Discrete Cosine Transform), reducing file size. Combining with resizing yields even greater compression.
Lossy vs. Lossless: Picking the Right Quality Level
Compression comes in two flavors. Lossy compression, used by JPG and WebP, permanently discards fine color detail that human eyes rarely notice, which is why it can shrink a photo dramatically. Lossless compression, used by PNG, rearranges data more efficiently without throwing anything away, so the savings are real but modest. For photographs, lossy is almost always the right call; for screenshots, logos, and diagrams with crisp lines and flat colors, lossless formats keep edges sharp.
As a practical rule of thumb with the quality slider: 80% is a safe default for photos headed to the web, 70% still looks fine for images that will be displayed small, and 90% or higher is worth it for photos people will zoom into or print. Watch for two telltale signs of over-compression in the preview: blocky smudges in smooth areas like skies, and fuzzy halos around text or high-contrast edges. If either appears, nudge the slider back up until they disappear — the size difference between 65% and 75% is often small, but the visual difference can be large.
Real-World Scenarios
Speeding up a slow website: Images are usually the heaviest part of a web page, and a single uncompressed camera photo can weigh more than all your scripts and styles combined. Compressing hero images and blog photos before upload is one of the highest-impact, lowest-effort performance wins available, and it directly improves Core Web Vitals metrics that search engines care about.
Getting past attachment limits: Many corporate mail servers and web forms reject files past a fixed size threshold. Instead of guessing, compress the image here and read the exact output size from the badge next to the preview, then adjust the slider until you are comfortably under the limit.
Preparing batches of listing or portfolio photos: If you photograph products or artwork, compressing each shot to a consistent quality level before upload keeps your pages fast without making some photos look visibly worse than others. Since the original file on disk is never touched, you can always come back and re-export at a different setting.
A Simple Workflow That Works Every Time
When in doubt, follow this routine: upload the image, compress once at the default 80%, and compare the two previews at full attention for a few seconds. If you cannot spot a difference, try 70% and check again; if you can, step back up to 85 or 90%. Because everything happens instantly in your browser with no upload wait, iterating like this takes seconds, and the size badges tell you exactly what each step buys you. For very large photos, consider resizing the dimensions first with the Image Resizer and compressing afterward — reducing a 4000px-wide photo to 1600px before compression typically saves far more than compression alone ever could.
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