A plain-language comparison of PNG, JPG and WebP, with rules of thumb for choosing the right one and tools to convert between them.

Picking an image format is a tradeoff between file size, quality, and what a piece of content needs to look like. Getting it wrong either bloats a page with unnecessarily large files, or quietly degrades photos and graphics. Here is how the three most common web image formats actually differ.

JPG (or JPEG)

JPG uses lossy compression, meaning it throws away some image data to shrink the file, and it does this especially well on photographs with lots of color gradients and detail. It does not support transparency. JPG is the right default for photos: product shots, hero images, backgrounds. The tradeoff is that pushing the compression too far introduces visible artifacts, especially around sharp edges and text, which is why JPG is a poor choice for screenshots, logos, or anything with flat colors and crisp lines.

PNG

PNG uses lossless compression, so no image data is discarded, and it supports transparency. That makes it the right choice for logos, icons, screenshots, and any graphic with flat colors, sharp edges, or text. The downside is file size: a PNG of a detailed photograph is typically much larger than the same image saved as a JPG, for a quality difference most people will not notice.

WebP

WebP is a newer format built specifically for the web, and it supports both lossy and lossless compression plus transparency, essentially covering what JPG and PNG each do separately, at a smaller file size for comparable quality. Browser support is now effectively universal, so there is rarely a reason to avoid it. The main reason people still use JPG and PNG is familiarity and compatibility with older tools and workflows, not any technical limitation of WebP.

Rule of thumb

• Photographs, backgrounds, anything without transparency: JPG, or WebP in lossy mode for a smaller file at similar quality.
• Logos, icons, screenshots, graphics with transparency: PNG, or WebP in lossless mode for a smaller file.
• Building a new website from scratch: default to WebP everywhere and only fall back to JPG or PNG if a specific tool in your workflow requires it.

Converting and compressing images

You do not need design software installed to switch formats or shrink a file that is too large to upload. SEOpeck's Image Compressor reduces file size with an adjustable quality slider so you can see exactly how much you are trading off. For format conversion, there are dedicated tools for every direction: JPG to PNG, PNG to JPG, JPG to WEBP, PNG to WEBP, WEBP to JPG and WEBP to PNG. If you need to resize an image rather than just compress it, the Image Resizer handles that separately.

Why this matters beyond file size

Image weight is one of the biggest levers on how fast a page loads, and page speed affects both user experience and how search engines evaluate a page. Serving an unnecessarily large PNG where a compressed WebP would look identical is one of the most common, and easiest to fix, sources of a slow page.