How to Convert PNG to WebP to Accelerate Website Page Speed

Heavy PNG images are a common reason for slow web pages. Lighter images make pages load faster, most noticeably for visitors on mobile data.

The power of WebP compression

WebP provides both lossy and lossless compression specifically engineered for the modern internet. Converting PNG graphics to WebP usually makes them clearly smaller while keeping transparent backgrounds. How much smaller depends on the picture.

How to convert PNG to WebP

1. Select your PNG graphics or banners.
2. Adjust the quality slider to your desired balance (80 to 90 percent is great for graphics).
3. Click Convert to WebP.
4. Download the WebP files.

All major modern browsers (Chrome, Safari, Firefox, Edge) natively display WebP images without requiring special plugins.

Worked example: a blog post with five screenshots

1. Before converting, check the pixel width of the screenshots. If your article column is 800 pixels wide and the screenshots are 2800 pixels wide, resize them first. No format change saves as much as removing pixels nobody will see.
2. Convert the resized PNG files to WebP at quality 90, since they contain text.
3. Compare each pair of sizes in the result list. Keep the WebP where it is clearly smaller.
4. Upload the WebP files and view the published post on a phone. Zoom into the text of one screenshot to confirm that it is still crisp.
5. Store the PNG files in a folder outside the website as your originals.

Common mistakes

• Converting without resizing. A huge picture in a better format is still a huge picture.
• Using one low quality value for everything. Photos tolerate it. Screenshots with small text do not.
• Replacing files on a live site without updating the links. If the page still points to image.png and you deleted it, visitors see a broken image.
• Converting logos that would be better as SVG. A logo drawn as vector artwork stays sharp at every size and is often smaller than any pixel format.
• Expecting a miracle for page speed. Images are one part of it. Slow hosting, heavy scripts and too many fonts are not fixed by WebP.

How to tell whether it helped

Measure before and after. The developer tools of your browser have a Network tab that lists every file a page loads together with its size, so you can add up the image weight with the old files and with the new ones. Free page speed tests from search engines and hosting companies also report image savings. If the total barely moves, your images were not the main problem.

When to leave PNG alone

Keep PNG for files people will download and reuse, such as press logos and templates, because not everyone can open WebP. Keep it as well for tiny interface icons, where the saving is a few bytes, and wherever your content system does not accept WebP uploads.

Checklist

• The images are resized to the width they are shown at.
• Quality is chosen per type of picture.
• Every link on the site points to a file that exists.
• The originals are stored safely.