Dynapik offers a free online tool to change image types - no need to download anything. It's quick and easy to use. You can change your PNG8 images to JXL format. This tool works for both professionals and casual users. Convert your images to JXL in seconds.
PNG-8 (8-bit Indexed)
The lightweight champion for simple graphics, offering GIF-like sizes with PNG quality.
PNG-8 is a specific variant of the PNG format that uses an 8-bit indexed color palette, limiting the image to a maximum of 256 colors. This is the same color technique used by GIF, but PNG-8 uses the superior DEFLATE compression algorithm, resulting in files that are typically even smaller than GIFs. PNG-8 is the secret weapon of web optimization. For logos, icons, and simple illustrations that don't need millions of colors, converting a standard 24-bit PNG to PNG-8 can reduce file size by 60-80% with virtually no visual difference. It supports transparency, usually in binary form (like GIF), though some modern tools can create PNG-8 files with full alpha transparency.
In a PNG-8 file, each pixel is represented by a single byte (8 bits) which acts as an index into a palette (PLTE chunk) of up to 256 RGB colors. This is much more efficient than storing the full 3-byte RGB value for every pixel. Transparency in PNG-8 is typically handled by the `tRNS` chunk, which specifies a single color index as transparent (binary transparency). However, the PNG specification allows the `tRNS` chunk to contain alpha values for palette entries, enabling semi-transparency. Tools like `pngquant` exploit this to create 'Alpha PNG-8' files that have both small size and smooth transparency, though very old browsers (IE6) struggled with this.
PNG-8 has been part of the PNG specification since version 1.0 (1996). It was designed to replace GIF, offering better compression and being patent-free. However, due to Internet Explorer 6's poor support for alpha transparency in PNGs, PNG-8 (with binary transparency) was often used as a fallback for years. Today, with modern tools like TinyPNG and pngquant, PNG-8 has seen a resurgence as an optimization target, allowing developers to serve crisp graphics at tiny file sizes.
JPEG XL
The true next-generation successor designed to replace JPEG, PNG, and GIF entirely.
JPEG XL (JXL) is the most advanced image format currently in existence. Unlike WebP and AVIF, which are derived from video codecs, JPEG XL was designed from the ground up specifically for still images. This gives it unique superpowers, such as the ability to losslessly re-compress existing JPEG files to be 20% smaller without losing a single bit of data. It offers best-in-class lossless compression (beating PNG), best-in-class lossy compression (beating JPEG), and supports features needed for professional workflows like CMYK, layers, and ultra-high resolutions. However, its adoption has been slowed by political battles, most notably Google Chrome's decision to remove support in 2022, though Apple has since added full support in Safari 17.
JPEG XL uses a combination of two coding modes: VarDCT (Variable Block-size DCT) for lossy images and Modular Mode for lossless/artistic images. Its 'killer feature' is legacy JPEG transcoding: it can take the DCT coefficients from an old JPEG file and repackage them into the more efficient JXL container. This process is reversible, meaning you can convert your entire JPEG library to JXL to save 20% space, and convert them back to the exact original byte-for-byte JPEGs later if needed. It also supports 'progressive decoding' far better than any other format, allowing a high-quality preview to appear almost instantly.
The JPEG committee began the call for proposals for a next-gen standard in 2017. The final standard (ISO/IEC 18181) was published in 2021/2022, combining the best parts of Google's PIK and Cloudinary's FUIF proposals. Despite being technically superior, its rollout hit a wall when the Chrome team removed the experimental flag in late 2022, citing lack of ecosystem interest. However, Apple's adoption in 2023 (iOS 17/macOS 14) has breathed new life into the format.
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Convert images files between over 20 formats. We support popular formats like PNG, JPG, WebP, HEIC and more.
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