Choosing PNG, JPEG or WebP for a browser export

Choose the input and output

The export choice changes how the file handles transparency, detail, and size. PNG preserves transparent pixels and is lossless for pixel data, so it is useful when edges or empty areas must remain clear. JPEG cannot represent alpha transparency; the tool flattens transparent areas to white. Its lossy quality buttons, such as 65, 80, or 95, affect size and detail, and selecting a higher quality does not recover original detail that was already removed.

WebP appears only if the browser encoder is available. Because availability is not guaranteed, check the actual output before relying on the option. Each format has different tradeoffs, so there is no universal smallest format for every image, and no format choice provides a guaranteed SEO benefit. Conversion is local, and the original file on the user's device remains unchanged.

A worked example

Start with the same 100 by 60 input image and export it at 50 by 30. If the image contains a transparent corner, PNG keeps that corner transparent after export. In JPEG, the same transparent corner becomes white because JPEG cannot store alpha pixels. The difference is visible if the exported image is placed on a colored background: the PNG version shows the background through the transparent area, while the JPEG version shows a solid white patch.

For lossy export, use a lower quality setting when file size matters more than fine detail. A JPEG exported at quality 65 is usually smaller than one exported at quality 95, but it may show more compression artifacts near text edges or contrasting lines. Moving from 65 to 95 does not bring back detail that was lost in the earlier export, so decide the quality before exporting.

Check the downloaded file

After downloading, open the image and check its dimensions, appearance and transparency. The tool checks the encoded output type before offering a download. Changing a filename extension does not convert a file, so keep the extension supplied by the exporter.

Limits and common mistakes

JPEG cannot produce a transparent result, so using it for logos or user interface assets with clear backgrounds is a mistake because transparent areas become white. PNG avoids that problem but may create a larger file for photographic content with many colors. WebP may be available in one browser but not another, so treat it as optional unless the browser encoder is verified.

A smaller file is not automatically better for search ranking, and the optimal format depends on the image content and required transparency. Do not assume that re-exporting a JPEG at high quality improves it. The original detail removed during lossy compression is gone, and the original input file stays unchanged during local conversion.