Compress PNG
Shrink PNG images directly in the browser. Transparency and image quality are preserved. No upload, no waiting — instant and free.
Understanding PNG compression
Important: PNG uses lossless compression. That means pure PNG compression (without changing colors) introduces no quality loss. JNRT Pixel re-encodes PNGs via the Canvas API, which significantly reduces file size.
Frequently asked about PNG compression
Is transparency preserved when compressing? +
Yes. JNRT Pixel fully preserves the alpha channel during PNG compression. Transparent areas stay transparent.
Why is my compressed PNG sometimes larger than the original? +
That can happen when the original was already well-optimized or when the image has properties (many colors, photos) for which PNG is generally inefficient. In those cases WebP is the better choice.
What is the difference between PNG-8 and PNG-24? +
PNG-8 supports up to 256 colors (like GIF); PNG-24 supports 16.7 million colors. JNRT Pixel uses the Canvas default, which outputs PNG-24.
About this tool
In shortLossless PNG optimization in your browser — palette reduction, pixel-exact preservation.
PNG was created in 1996 because GIF was encumbered by Unisys patents, and the early web needed a free, lossless format with transparency. Three decades later PNG is still the standard for everything that is not a photograph: logos, icons, diagrams, screenshots, pixel art. Unlike JPG, PNG is lossless — no pixel is altered, no detail is lost. Compression is purely the result of clever data packing (Deflate, LZ77, filter prediction). This tool optimizes PNG files locally in your browser using three levers. Palette reduction for PNG-8 (images with fewer than 256 colors are stored in an indexed palette, drastically shrinking the file). Filter optimization — PNG writes a filter byte before each scanline relating its content to the previous row; the optimal filter choice makes subsequent Deflate compression more efficient. Removal of unused chunks — preview thumbnails, redundant color profiles, Photoshop editing history, sometimes even embedded EXIF blobs. How much can you save? PNGs exported from Photoshop or GIMP often shrink by 30–60% without changing a single visible pixel. Already-optimized PNGs may yield another 5–15%. Screenshots depend heavily on content: software UIs with large solid areas compress dramatically better than photographic content. When is PNG the right choice? Logos and brand marks (hard edges, frequent transparency), diagrams and infographics (clean lines, text), UI screenshots (pixel-exact software interfaces), and pixel art. For photos, PNG is extremely inefficient — a smartphone photo as PNG is 3–10× larger than the equivalent JPG. If your image is a photo, convert to JPG, WebP or AVIF — the Multi-Format Compare shows you the savings side by side. Keeping transparency. PNG's biggest advantage over JPG is the alpha channel. Crucial for logos that need to work on varied backgrounds, icons in dark and light UIs, and PWA app icons (see PWA Generator). Converting to JPG strips transparency and replaces it with a flat background color. If transparency matters, stay on PNG or switch to WebP-Lossless (which also supports alpha and is typically 20–40% smaller than PNG). Compared to modern alternatives. WebP-Lossless (since 2014) delivers 20–40% smaller files than optimized PNG for graphics. AVIF-Lossless is even more efficient but slower to encode. For a web-only audience, consider serving a WebP asset in parallel. More in PNG vs. WebP. Privacy and processing. Like all JNRT Pixel tools, this PNG optimizer runs entirely in your browser. No upload, no storage, nobody but you sees your images — important for screenshots of internal applications or sensitive design materials. Related: PNG vs. WebP, JPG vs. PNG, image compression for web — 2026 guide.