What is a PNG File?

PNG is the most-used image format on the web. W3Techs measures it on 76.1% of all websites as of August 2026, ahead of JPEG (70.2%) and SVG (67.3%). Two features earned PNG that spot: transparency and lossless compression.

Transparency support

PNG supports alpha-channel transparency, meaning each pixel can be fully opaque, fully transparent, or anywhere in between. That’s what lets a logo, icon, or product image sit cleanly on any page background, and it’s why MDN’s image file type guide recommends PNG over JPEG for more precise reproduction of a source image or when transparency is needed.

The older formats don’t come close here. JPG has no transparency at all, and GIF manages only 1-bit transparency: each pixel is either fully visible or fully invisible, which leaves rough edges around curves and text.

Lossless compression

PNG is a lossless image format. Compression shrinks the file without discarding any image data, so you can open and re-save a PNG as often as you like and every pixel comes back exactly as it went in. That makes it the strongest of the classic web formats for high-contrast, detailed images like screenshots, text, and line art. PNG was designed to replace the older GIF format, and it typically compresses 5% to 25% smaller than the same image saved as a GIF, per libpng.org, the format’s home site.

Photos are the exception. A lossy JPG discards detail your eye barely registers, so a photograph saved as JPG is usually far smaller than the same photo as PNG. The rule of thumb: PNG for fidelity and transparency, JPG for photographic file size.

PNG vs. JPG, GIF, SVG, and WebP

Each common web image format has a job it does best:

• PNG: screenshots, logos, line art, text-heavy graphics, and anything that needs transparency.
• JPG: photographs, where lossy compression produces far smaller files.
• GIF: mostly legacy use; PNG compresses still images better, and newer formats animate better.
• SVG: icons and diagrams that must stay sharp at any size, because it’s vector rather than raster.
• WebP and AVIF: better compression than PNG or JPG, plus transparency and animation support.

For a step-by-step walkthrough of converting a site to modern formats, see our guide So Long, JPG: Here’s How To Optimize Images for the Modern Web.

PNG’s drawbacks

PNG’s two real drawbacks are file size and print. Photos saved as PNG run much larger than JPG, WebP, or AVIF versions, and PNG has no CMYK color support, so images bound for professional printing usually need converting to another format first.

Animation is no longer the gap it once was. Animated PNG (APNG) works in Chrome, Edge, Firefox, Opera, and Safari. For animation, APNG, WebP, or AVIF compresses better than GIF, while SVG suits animated icons and interface graphics.

Are PNG files scalable?

No. A PNG stores a fixed grid of pixels, so enlarging it past its native dimensions blurs and pixelates the image. Export PNGs at the largest size you’ll need, and switch to a vector file format like SVG for graphics that have to scale to any size.