Compress PNG Files

PNG is a lossless format. Every pixel in the original appears in the output — unchanged. But PNG files carry overhead. Ancillary metadata chunks. Unoptimized DEFLATE streams. Oversized color palettes with thousands of entries when the image uses 47 distinct colors.

Picture Optimizer strips unnecessary chunks first. It analyzes the color histogram. If the image uses fewer than 256 colors, the engine converts it to an indexed-color palette — cutting file size by 60–80%. For true-color PNGs, it re-encodes the DEFLATE stream at maximum compression. The alpha channel stays intact.

PNG files compress well. But converting PNG to AVIF compresses them dramatically. One test case: a 1.2 MB product screenshot as PNG. The same image as AVIF: 12 KB. That is a 99% reduction. The AVIF output displayed crisper edges around text than the PNG original.

AVIF uses the AV1 codec — built for video, adapted for still images. It handles transparency natively. It compresses flat-color areas (common in screenshots and UI mockups) with near-zero overhead. Picture Optimizer runs this conversion in a single pipeline step.

Keep PNG when your audience includes Internet Explorer users or very old Android WebView browsers that lack WebP/AVIF support. Keep PNG for favicon .ico fallbacks. Keep PNG when you need exact pixel-level reproduction with no generation loss — print-resolution logos, technical diagrams, or medical imaging.

For everything else — screenshots, UI mockups, product photos with transparency — convert to WebP or AVIF and save 70–99% of file weight.

The WordPress plugin handles PNG files identically to JPG. Select your PNGs in the Media Library. Choose your pipeline mode and output format. If you select WebP or AVIF as the target format, the plugin converts and replaces the file, updates all URLs in your content, and adds .htaccess redirects for any cached external references pointing to the old .png URL.