Choosing between PNG and JPG isn't just a design choice; it's a critical technical decision that impacts your website's PageSpeed Insights score, Core Web Vitals, and ultimately, your Google ranking. As we move further into 2026, the nuances of image compression have become more complex. This guide breaks down everything from bit depth to chroma subsampling to help you make the right choice for your digital assets.
JPEG (Joint Photographic Experts Group) is the most common image format used by digital cameras and web users. Its primary strength lies in its lossy compression algorithm.
A typical high-resolution photograph can be reduced from 10MB to 500KB using JPG compression without significant visible degradation. This is crucial for image converters that aim to balance quality and speed.
PNG (Portable Network Graphics) was created as an improved, non-patented replacement for GIF. Unlike JPG, PNG uses lossless compression (specifically the DEFLATE algorithm), meaning no data is lost during the saving process.
The standout feature of PNG is its support for transparency. If you have a logo or a product image that needs to sit on a colorful background, PNG to JPG conversion is a bad idea because JPG will replace the transparency with a solid white or black color.
| Feature | JPG (Joint Photographic) | PNG (Portable Network) |
|---|---|---|
| Compression Type | Lossy | Lossless |
| Transparency | No | Yes (8-bit and 24-bit) |
| Color Support | 16.7 Million Colors | 16.7 Million + Alpha Channel |
| Ideal For | Real-world Photos | Logos, Screenshots, Graphics |
1. Does converting PNG to JPG speed up my site?
Almost always. For non-transparent images, a JPG is typically 5-10 times smaller than a PNG.
2. Can a JPG be lossless?
Technically there is a "Lossless JPEG" standard, but it is rarely supported by web browsers.
Use JPG for every photograph on your site. Use PNG only when you need transparency or have text-heavy graphics that need pixel-perfect clarity. If you're looking for the ultimate performance, consider converting both to WEBP.