APNG Compressor
Compress animated PNG (APNG) files by reducing frame count and optimizing color depth — entirely in your browser. Our free APNG compressor uses frame skipping and color quantization to reduce file sizes, with a side-by-side preview so you can verify quality before downloading. No signup, no server uploads, 100% private.
APNG compression works by reducing the number of frames (frame skipping) and the number of colors per frame (color quantization). The first compression may take a few seconds while the decoder initialises.
Frame reduction is most effective on high-FPS animations.
Fewer colors = smaller file. 256 colors is near-lossless for most animations.
Why Use Our APNG Compressor?
Instant APNG Compression
Compress animated PNG files directly in your browser using a WebAssembly-powered APNG encoder. Our APNG compressor processes frames locally for maximum speed — no server uploads, no waiting.
Secure APNG Compressor Online
Your animated PNG files never leave your device when you compress APNG online. 100% client-side processing ensures complete privacy for proprietary animations and unreleased content.
APNG Compressor Online — No Installation
Compress APNG files directly in your browser with zero software downloads or plugins. Our free APNG compressor works on any device with a modern browser — Mac, Windows, or Linux.
Frame Reduction & Color Quantization
Two independent compression levers: reduce frame count (keep every 2nd, 3rd, or 4th frame) and reduce color depth (4–256 colors). Combine both for maximum APNG file size reduction.
Common Use Cases for APNG Compressor
Web Animation Optimization
Compress APNG animations for web use to reduce page weight and improve load times. Smaller APNG files directly improve Core Web Vitals scores and reduce bandwidth costs for high-traffic pages.
Mobile App Animations
Reduce APNG animation file sizes for iOS and Android apps where bundle size matters. Compress APNG files to hit target sizes for app store submissions and OTA update packages.
Email & Messaging Animations
Compress APNG stickers and animated images for email newsletters and messaging platforms. Smaller APNG files load faster in email clients and stay within attachment size limits.
Slack & Discord Custom Emoji
Slack and Discord enforce strict file size limits on custom animated emoji. Use the APNG compressor to reduce animated PNG stickers to under 512 KB for platform upload requirements.
Documentation & README Animations
Compress APNG screen recordings and demo animations for GitHub READMEs and documentation sites. Smaller APNG files load faster in browsers and reduce repository size.
UI Loading & Micro-Animations
Compress APNG loading spinners, progress indicators, and micro-animations for web and app UIs. Reducing APNG file size improves perceived performance and reduces initial page load weight.
Understanding APNG Compression
What is APNG Compression?
APNG (Animated PNG) is an extension of the PNG format that supports multi-frame animations while maintaining full alpha channel transparency — unlike GIF, which is limited to 256 colors and binary transparency. APNG compression reduces the file size of animated PNG files by applying two techniques: frame reduction (removing frames to lower the frame count) and color quantization (reducing the number of unique colors per frame). Our free APNG compressor applies both techniques entirely in your browser using the UPNG.js library — no server uploads required.
How Our APNG Compressor Works
- Upload Your APNG File: Drop any .png or .apng file into the drop zone. The APNG compressor automatically detects the frame count, dimensions, and frame delays. Static PNG files are also supported.
- Configure Compression Settings: Choose a frame reduction level (keep every 2nd, 3rd, or 4th frame) and a color quantization level (4–256 colors, or lossless). The tool shows the expected output frame count before you compress. All processing happens locally in your browser — your files never leave your device.
- Download Compressed APNG: After compression, the tool shows a side-by-side preview of the original and compressed animations with exact size savings. Download the compressed APNG file directly.
What Gets Changed During APNG Compression
- Frame Count Reduction: Frame skipping removes intermediate frames and accumulates their delays into the kept frames — the animation plays at the same total duration but with fewer frames and a lower file size.
- Color Quantization:Each frame's RGBA pixel data is reduced to a palette of N colors using median-cut quantization. Fewer colors means smaller compressed data per frame.
- Delta Frame Optimization: UPNG.js automatically optimizes delta frames during re-encoding — only storing the changed pixels between frames rather than full frame data.
- Metadata Stripping: Re-encoding removes embedded metadata chunks (tEXt, iTXt, zTXt) that are not needed for rendering, contributing to additional size savings.
Important Limitations
Frame reduction changes the animation's smoothness — keeping every 2nd frame halves the frame rate, which may be noticeable on fast animations. Color quantization below 64 colors may produce visible banding on photographic or gradient content. For best results, start with 256 colors (near-lossless) and frame skip 2, then increase compression if needed. Very large APNG files (above 10 MB or 100+ frames) may take several seconds to process on older devices.
Related Tools
PNG to RAW
Convert PNG images to RAW format instantly - Free online PNG to RAW converter
JPG to RAW
Convert JPG/JPEG images to RAW format with customizable bit depth - Free online JPG to RAW converter
BMP to RAW
Convert BMP images to RAW format instantly - Free online BMP to RAW converter
GIF to RAW
Convert GIF images to RAW format instantly - Free online GIF to RAW converter
Frequently Asked Questions About APNG Compressor
An APNG compressor is a tool that reduces the file size of Animated PNG files by applying frame reduction and color quantization. Our free APNG compressor processes files entirely in your browser using the UPNG.js library — no server uploads required.
APNG supports full 24-bit color (16 million colors) and full alpha channel transparency, while GIF is limited to 256 colors and binary (on/off) transparency. APNG files are typically larger than GIF but produce much higher quality animations, especially for content with gradients, shadows, or semi-transparent pixels.
Absolutely. Our APNG compressor online processes everything locally in your browser using the UPNG.js WebAssembly library. Your animated PNG files are never uploaded to any server. All compression happens on your device for complete privacy.
Yes. Our APNG compressor is 100% free with no signup, no premium tier, no file size limits, and no watermarks on compressed files.
Frame reduction keeps every Nth frame and removes the frames in between. The delays of removed frames are added to the kept frame, so the total animation duration stays the same — the animation just plays at a lower frame rate. Keeping every 2nd frame halves the frame count and typically reduces file size by 30–50%.
Color quantization reduces the number of unique colors in each frame to a palette of N colors. 256 colors is near-lossless for most animations. 64 colors is good for simple graphics and icons. Below 32 colors, visible banding may appear on gradients and photographic content. The side-by-side preview lets you judge quality before downloading.
Yes. The APNG compressor also works on static PNG files. For static PNGs, frame reduction has no effect, but color quantization still applies and can significantly reduce file size for images with limited color ranges.
This can happen when the original APNG was already heavily optimized, or when using lossless color settings (no quantization) on a file that was previously encoded with a different compressor. Try enabling color quantization at 256 colors to achieve size reduction without visible quality loss.
For Slack and Discord custom emoji (512 KB limit), start with frame skip 2 and 128 colors. If the file is still too large, increase to frame skip 3 and 64 colors. The side-by-side preview helps you verify the animation still looks good at the chosen settings.