Why Format Choice Matters
The image format you choose affects three things: file size, visual quality, and browser support. Making the wrong choice leads to slow-loading pages (over-sized photos), washed-out quality (lossy compression on the wrong content), or broken display on older devices.
Here is a practical breakdown of the three formats you will most often encounter.
JPEG – The Photo Standard
JPEG (also written JPG) is a lossy compression format. It discards image data during compression to achieve smaller file sizes. The amount of data discarded is configurable through a quality setting (typically 0–100).
Best for: Photographs, complex images with gradients and many colors, any image where a small loss of sharpness is acceptable.
Not ideal for: Screenshots, line art, text overlays, logos, images that need sharp edges or transparency.
Typical file size advantage: A high-quality JPEG is usually 60–80% smaller than a lossless PNG of the same photo.
Key limitation: Every time you save a JPEG (edit → save → edit → save), you lose more quality. Always keep an original in a lossless format (PNG, TIFF) if you plan to re-edit.
JPEG does not support transparency (alpha channel).
PNG – Lossless and Transparent
PNG uses lossless compression – no image data is discarded. What you put in is exactly what you get out.
Best for: Screenshots, interface graphics, logos, text overlays, images with sharp edges, any image requiring a transparent background.
Not ideal for: Photographs (file sizes are very large compared to JPEG for equivalent quality).
Key advantage: Supports full alpha channel transparency, making it the standard for UI elements, overlays, and images that need to sit on different background colors.
PNG is the safe default when quality cannot be compromised and file size is secondary.
WebP – The Modern Replacement
WebP was developed by Google and supports both lossy and lossless compression. It achieves smaller file sizes than JPEG and PNG for equivalent quality.
Best for: Web images in general – it is designed specifically for the web. Both photos and graphics benefit.
File size advantage:
- WebP lossy vs JPEG: ~25–35% smaller at equivalent quality
- WebP lossless vs PNG: ~26% smaller on average
Browser support: Excellent – all modern browsers (Chrome, Firefox, Safari 14+, Edge) support WebP. If you need to support very old browsers (IE, Safari 13 and below), you still need a fallback.
Transparency: Supported in both lossy and lossless WebP modes.
The <picture> element in HTML lets you serve WebP with a JPEG/PNG fallback:
<picture>
<source srcset="image.webp" type="image/webp">
<img src="image.jpg" alt="Description">
</picture>
AVIF – The Emerging Contender
AVIF is a newer format with even better compression than WebP (typically 20–50% smaller than WebP lossy). Browser support is growing fast but is not yet universal. Worth watching for future projects.
Practical Decision Guide
| Situation | Recommended format |
|---|---|
| Photograph for a webpage | WebP (JPEG fallback) |
| Logo with transparency | WebP lossless or PNG |
| Screenshot | PNG |
| Icon / UI element | WebP or PNG |
| Email image | JPEG (widest support) |
| Print source file | PNG or TIFF |
Converting Between Formats in Your Browser
The Image Converter on this site converts between JPEG, PNG, and WebP entirely in your browser – no upload to a server, no file size limits beyond your RAM. You can also adjust quality for lossy formats to tune the size/quality trade-off.
Summary
- JPEG: photographs, accepts some quality loss, no transparency
- PNG: lossless, transparency, logos and screenshots
- WebP: best of both worlds for the web, slightly less universal support
- When in doubt for web use: WebP first, JPEG fallback for photos, PNG for transparency