PNG Compressor
Compress PNG images to reduce file size with automatic, content-aware optimization. Optimize your PNG files for faster web loading while keeping transparency intact and quality changes imperceptible for typical graphics and screenshots.
Upload Files
Drag and drop your PNG files here, or click to select (max 5 files)
Up to 10 MB per PNG
Selected Files
Selected files will appear here
Upload PNG files to start compressing
About PNG Compression
- • Upload up to 5 PNG files at once, 10 MB each; requests time out after 90 seconds
- • Each file is compressed individually with progress tracking
- • Compression is automatic: colour-palette quantisation followed by a lossless re-deflate pass, picking whichever result is smallest
- • Logos, screenshots and graphics with flat colour areas see the largest savings
- • Photographs saved as PNG compress less — consider PNG to JPG or PNG to WebP instead
- • Transparency is always preserved
- • If the original was already well-optimised, the tool keeps it unchanged rather than making it larger
- • Use individual download buttons or download all files as a ZIP
About PNG Compressor
The PNG compressor automatically reduces PNG file sizes by combining colour-palette optimisation with a lossless re-encoding pass, then keeps whichever result is smaller. This tool optimizes PNG files for faster web loading, reduced bandwidth usage, and improved website performance, keeping transparency intact and quality changes imperceptible for typical graphics and screenshots.
Why use a PNG Compressor?
Compressing PNG files reduces loading times, improves website performance, and decreases bandwidth costs while keeping transparency intact. Smaller PNG files enhance user experience, improve SEO rankings, and reduce storage requirements — automatic quality selection keeps visual changes imperceptible for typical graphics, screenshots, and UI assets.
Who is it for?
This tool is perfect for web developers optimizing site performance, e-commerce platforms improving page load speeds, photographers reducing file sizes for online portfolios, and content creators needing smaller PNG files without compromising transparency or quality.
How to use the tool
Upload your PNG files using the file picker or drag-and-drop interface (up to 5 files, 10 MB each)
Files that aren't valid PNGs (checked against the PNG signature) or exceed the 10 MB limit are rejected with an explanation before compression starts
Click Compress to send the files one at a time to the compression pipeline — there is no compression level to configure
Watch each file's status move from Ready to Compressing to Completed, with the elapsed time shown while it's in progress
Cancel an in-progress compression at any time with the Cancel button next to the elapsed-time display
Review the original size, compressed size, and percentage saved for each file — or an Already optimal message if no smaller output was found
Download your optimized PNG files individually, or click Download All to get every completed file at once as a ZIP
Frequently Asked Questions
How do I compress a PNG image online?
Drag and drop your .png file. The compressor reduces file size via colour quantisation (reducing the palette to optimal colours for the image content) and DEFLATE optimisation, while keeping the format lossless. Download the smaller .png result. Conversion runs through our image pipeline; files are not stored or logged after processing. Typical reductions for graphics/screenshots: 30-70%. For photographs saved as PNG, the savings are smaller and you should consider converting to JPG, WebP, or AVIF instead.
Will compressing my PNG reduce its quality?
There's no separate lossless or lossy mode to pick — every upload runs the same automatic pipeline: the colour palette is quantised to the smallest set that keeps a target quality level, then the result is losslessly re-encoded. For screenshots, UI graphics, and icons the quality change is normally invisible. For photographs with smooth gradients, slight banding can occasionally be visible. If a small-enough palette can't reach an acceptable quality, the tool keeps your original pixels rather than degrading them further.
Are my images uploaded to a server?
Your image is processed by our image pipeline and returned to your browser. We don't store, log, or share your images — they're discarded immediately after processing. TLS protects images in transit. For maximum privacy, run PNG compression locally with optipng (`optipng -o7 input.png`), pngcrush, or ImageMagick. For palette quantisation, use pngquant (`pngquant input.png`).
How much can I reduce the file size?
Depends on content type. Screenshots and graphics with flat colour areas typically compress 40-70%. Photographs saved as PNG see smaller savings (10-30%) — they should be converted to JPEG, WebP, or AVIF instead. UI elements, logos, and icons see the largest savings. The compressor tries multiple compression strategies and picks the smallest output. For aggressive size reduction on photographic PNGs, use [PNG to JPG](/tools/png-to-jpg/) or [PNG to WebP](/tools/png-to-webp/).
What is PNG and how does it compress?
PNG (Portable Network Graphics, 1996) is a lossless raster format. Its compression uses DEFLATE (the same algorithm as ZIP), preceded by 'filtering' steps that transform pixel data into a more compressible form. The compressor's job is to find the optimal filter strategy and palette representation for the specific image content. PNG works well for graphics, screenshots, and line art; it's inefficient for photographs (use JPEG/WebP/AVIF instead).
Why isn't my photograph compressing much?
Because PNG is a poor format for photographic content. Photos contain continuous-tone gradients and fine detail that don't compress well with DEFLATE — every pixel is slightly different. PNG compresses well when images have large flat colour areas, which photos lack. For photographic content, convert to a better-suited format: [PNG to JPG](/tools/png-to-jpg/) for compatibility, [PNG to WebP](/tools/png-to-webp/) for modern web, or [PNG to AVIF](/tools/png-to-avif/) for maximum compression.
Can I control the compression aggressiveness?
No — there's no aggressiveness slider or quality setting to pick. The compressor analyses each image and automatically selects the palette-quantisation and re-encoding parameters, then keeps whichever output is smaller than the original. This removes the guesswork of picking a level: screenshots and UI graphics automatically get the largest reduction, while photographic PNGs see smaller gains regardless of settings. For photographic content, convert to JPEG, WebP, or AVIF instead of trying to force more out of PNG.
When should I compress PNG vs convert to a different format?
Compress when you need to keep PNG (transparency requirement + legacy compatibility, or content type is graphics/screenshots that compress well). Convert when content is photographic and modern formats are acceptable: [PNG to WebP](/tools/png-to-webp/) gives ~70% additional savings, [PNG to AVIF](/tools/png-to-avif/) ~90%. Combine with [Image Resizer](/tools/image-resizer/) for maximum size reduction — compressing a 4K screenshot at half resolution typically saves more than aggressive compression at full size.
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