Comparison

PNG vs JPG: Which Format Should You Use?

April 5, 2025·6 min read

PNG and JPG are the two most widely used image formats on the web, but they serve very different purposes. Choosing the wrong format can bloat your page load times or degrade your image quality. This guide breaks down exactly when to use each format so you can make the right call every time.

How JPG compression works

JPG uses lossy compression, which means it discards some image data to achieve smaller file sizes. The algorithm groups pixels into 8x8 blocks and approximates colors, which works brilliantly for photographs with smooth gradients. The trade-off is that every save cycle degrades quality slightly, and sharp edges can develop visible artifacts.

How PNG compression works

PNG uses lossless compression, meaning no data is ever discarded. The file size is larger, but the image is pixel-perfect every time you open it. PNG also supports an alpha channel for transparency, making it essential for logos, icons, and overlays. However, PNG files of photographs can be 5-10 times larger than their JPG equivalents.

When to choose JPG

Use JPG for photographs, social media images, and any content where file size matters more than pixel-perfect accuracy. Blog hero images, product photos, and backgrounds are ideal candidates for JPG. At quality 85, most people cannot tell the difference from the original.

When to choose PNG

Use PNG for logos, icons, screenshots, diagrams, and any image with text, sharp lines, or transparency. PNG is also the right choice when you need to edit and re-save an image multiple times without quality degradation. If your design has fewer than 256 colors, PNG-8 offers surprisingly small file sizes.

The modern alternative: WebP

WebP combines the best of both worlds: lossy and lossless modes, transparency support, and file sizes 25-35% smaller than equivalent JPG or PNG. All modern browsers support WebP. If you are building a website today, WebP is often the best default choice.