JPG vs PNG vs WebP: Which Image Format Is Best for Your Website in 2025?

Why format choice matters as much as compression

Most people think of image optimisation as purely a quality/compression trade-off. But format choice happens before any compression settings are applied, and it can determine whether your starting point is 247KB or 1.4MB for the exact same photograph. Getting the format right first means compression does less work and the result looks better.

The three formats that dominate web image delivery each make fundamentally different trade-offs. Understanding those trade-offs is what turns format selection from guesswork into a deliberate, repeatable decision.

JPEG — the reliable workhorse that's been around since 1992

JPEG uses lossy compression — it permanently discards image data to achieve smaller file sizes. The compression is optimised for photographic content, exploiting the fact that human eyes are more sensitive to brightness variation than colour variation. This makes it excellent for photos but poor for graphics containing text, sharp lines, or solid colour areas (where the compression creates visible artifacts called "mosquito noise").

JPEG doesn't support transparency. If you need a transparent background, JPEG is not an option regardless of its other advantages. It's also worth knowing that JPEG quality degrades with every re-save — each time you open a JPEG, edit it, and save again, a new round of lossy compression is applied on top of the existing compression artifacts. Always keep originals in a lossless format.

Best for: Photographs on websites, email campaigns, social media uploads (platforms recompress anyway), situations requiring universal compatibility with very old software.

PNG — perfect quality with a file size penalty for photos

PNG uses lossless compression — every single pixel is stored exactly as it was, with no data discarded. This makes it ideal for situations where precision matters: screenshots showing UI elements with sharp text, logos with transparent backgrounds, digital illustrations with flat colours, and any image that will be edited further. PNG supports full alpha channel transparency.

The catch is file size. A 1200×800 travel photograph saved as PNG is typically 1.2–1.8MB. The same photo as a high-quality JPEG is around 200–280KB. That 5–7x size difference is a massive performance penalty for photographic content. For photos on websites, PNG makes no practical sense unless transparency is specifically required.

Best for: Logos and icons with transparency, screenshots and UI documentation, graphics with text overlays, images that will be edited and re-saved multiple times.

WebP — smaller than both, with the advantages of both

WebP was developed by Google specifically to improve web image delivery. It supports both lossy and lossless compression modes, supports alpha channel transparency in both modes, and typically produces files 25–35% smaller than JPEG at equivalent visual quality. At lossless quality, WebP is roughly 26% smaller than PNG for the same image.

Browser support crossed the 96% threshold in 2022 and now sits above 97% globally. The remaining 3% is almost entirely Internet Explorer 11 (effectively end-of-life) and some older Safari versions pre-14.0. For practical purposes in 2025, you can use WebP for everything on the web without any meaningful compatibility concern.

Best for: Essentially everything displayed in a modern web browser. Photos, graphics, images with transparency — WebP handles all of them better than the alternatives in terms of file size.

Real file size comparison — the same photograph across formats

Here's how a 1200×800 travel photograph (a typical blog post image) compares across formats at similar visual quality. These are real measurements, not estimates:

The takeaway: WebP lossy is 34% smaller than JPG at equivalent visual quality for this image — and that number holds fairly consistently across different photographic content. On a page with ten images, that's the difference between 2.5MB and 1.6MB of image payload.

The quick decision table

Converting your existing images

If you have a library of JPG images on your website, converting them to WebP is one of the highest-impact optimisations you can make right now. Our free image converter handles all format combinations — JPG to WebP, PNG to WebP, WebP to JPG — and processes everything in your browser with no uploads required. You can batch convert up to 20 images at once.

After converting, you can also use our image compressor to hit exact file size targets if you need specific sizes for an upload portal or CMS.