Image Formats Explained: JPEG vs PNG vs WebP vs BMP

The format you save an image in decides three things at once: how big the file is, whether it can have a transparent background, and how much detail survives each time you save it. This guide covers the four formats you'll meet most often with everyday images, and when to use each one.

JPEG

Best for: photographs and images with smooth gradients.

JPEG uses lossy compression: to make the file smaller, it permanently throws away detail your eye is unlikely to miss. You choose the trade-off with a quality setting. Higher quality keeps more detail and makes a bigger file; lower quality makes a smaller file with visible blocky artifacts, especially around sharp edges and text.

Three things to remember about JPEG: it handles millions of colours well, it does not support transparency, and it loses a little more detail every time you open, edit and re-save it. Keep your original file and export a JPEG copy at the end. Our image compressor lets you try different quality settings and compare the resulting file sizes before you download.

PNG

Best for: logos, icons, screenshots, images with text, and anything that needs a transparent background.

PNG uses lossless compression, so the image you open is pixel-for-pixel identical to the one you saved. It supports a full alpha channel, which means smooth, partly transparent edges rather than the single see-through colour GIF allows. That makes it the usual choice for logos and interface graphics that sit on different backgrounds.

For photographs, PNG files are usually much larger than JPEGs of the same picture. Where PNG wins is sharp edges, text and flat colour, exactly where JPEG artifacts are easiest to see. If you convert a JPEG to PNG, the file gets bigger but the quality doesn't improve: the detail JPEG already discarded can't come back.

WebP

Best for: images on modern websites.

WebP was developed by Google and supports both lossy and lossless compression, plus transparency and animation. According to Google, WebP lossless images are 26% smaller than PNGs, and lossy WebP images are 25–34% smaller than comparable JPEGs at equivalent quality. Results on your own images will vary, so it's worth comparing.

All current major browsers display WebP. If you need to support very old browsers, serve WebP with a JPEG or PNG fallback using the HTML <picture> element. Our compressor, converter and resizer can all save WebP.

BMP

Best for: older Windows software and some specialist programs.

BMP usually stores pixels with no compression at all, so files are large. A 1920 × 1080 image at 24 bits per pixel holds 1920 × 1080 × 3 = 6,220,800 bytes of pixel data, about 6.2 MB, before any header. BMP is rarely a good choice for the web. If you have BMP files, our format converter can open them and save them as PNG, JPEG or WebP.

Quick comparison

Which one should you pick?

• A photo for a website: WebP, or JPEG if the place you're uploading to doesn't accept WebP.
• A logo or icon that needs a transparent background: PNG, or WebP if your site supports it.
• A screenshot with text: PNG.
• An old BMP file: convert it to PNG to keep every pixel, or to JPEG or WebP for a much smaller file.

All ForgePX tools process your images locally in your browser, so the files aren't uploaded to a server.

Sources

Checked on 23 October 2026.

• Google for Developers: An image format for the Web (WebP)
• MDN: Image file type and format guide