PNG vs JPEG vs WebP: Choose a Web Image Format

Match the format to the source content

PNG provides lossless pixel encoding and supports alpha transparency, making it useful for flat graphics and sharp text. JPEG is commonly used for photographs and trades information for a smaller representation. WebP supports efficient still-image delivery and transparency. Browser canvas encoders expose particular modes and quality controls; a tool’s available options do not describe every feature supported by the file format itself.

Flatten transparency deliberately for JPEG

JPEG has no alpha channel. A transparent logo needs a chosen background when converted, and this site’s converter uses white. Check edge pixels for halos on the final page background. Changing a file extension alone does not convert the image, and turning a previously compressed JPEG into PNG does not recover the detail already discarded by the earlier encoding.

Measure dimensions and bytes separately

A format conversion keeps dimensions in our converter, while the resizer changes pixel dimensions and the compressor exposes lossy quality settings. Already optimized sources can grow after another encoding, so inspect the reported byte counts. Canvas exports also omit source metadata and animation. Keep an original source file and choose a separate delivery derivative for each practical display size.

Worked example

Transparent icon → PNG or WebP
Photo delivery → compare JPEG and WebP exports
Tiny screenshot text → inspect lossless PNG before choosing lossy output

Does WebP always produce a smaller file?

No. Content, dimensions, source encoding and encoder settings all affect the result. Compare actual exported byte counts.

Reference and further reading

Read the official documentation ↗