You upload an image to your site and PageSpeed Insights tells you to "serve images in next-gen formats". You need an image with a transparent background and you only have it in JPG, which doesn't support transparency. An old system only accepts ICO. Every image format exists for a technical reason, and choosing wrong costs you unnecessary quality, size or compatibility.
The formats, explained by what they actually solve
- PNG: lossless, with transparency support. The right choice for logos, screenshots with crisp text, or any image that needs a transparent background.
- JPG: lossy, no transparency, very universally compatible. Ideal for photographs, where quality loss with good compression is nearly imperceptible and the size savings are considerable.
- WebP: developed by Google, offers better compression than JPG and PNG while keeping similar quality, and it does support transparency. It's the recommended format today for most web images, with practically universal support in modern browsers already.
- AVIF: the newest format and the one with the best compression of all, often significantly cutting size compared to WebP at equivalent quality. Its browser support is somewhat more recent than WebP's, though it already covers the vast majority of users.
- BMP: uncompressed, impractical for the web due to its size, but still used in specific contexts like old software or lossless image processing.
- ICO: the Windows icon format, capable of including several resolutions within the same file; it's the format you need for a desktop app's icon or a classic favicon.
How to convert an image
- Upload the image in its original format.
- Choose the destination format.
- Download the converted result.
You can do it free with the image converter on this site, 100% in your browser and no sign-up.
Why WebP and AVIF matter so much for web performance
Performance audit tools like Google PageSpeed Insights directly penalize using JPG and PNG where WebP or AVIF would give the same visual result with a lighter file. Converting a site's images to these modern formats is one of the simplest performance improvements to apply, with a direct impact on perceived load speed.
How to choose quickly
- You need transparency and maximum compatibility: PNG.
- It's a photograph and size matters: JPG, or better yet, WebP.
- You want the best web performance possible today: AVIF, with WebP as a fallback if you need extra compatibility.
- You need an icon for Windows or a classic favicon: ICO.
Frequently asked questions
Are WebP and AVIF compatible with all browsers? Compatibility is already very wide in modern browsers; for maximum retro compatibility, PNG or JPG remain the safer choice.
Does converting JPG to PNG improve quality? No, PNG can't recover information the JPG already lost when compressed; it only changes the container.
Can I generate an ICO with several resolutions? Yes, the ICO format supports including multiple sizes in the same file, useful for icons displayed at different sizes depending on context.
Is my image uploaded to any server? No, the conversion happens entirely in your browser.
Convert your images between PNG, JPG, WebP, AVIF, BMP and ICO for free with the image converter, 100% in your browser and no sign-up.