Three image formats dominate the web and most everyday document use: JPG, PNG, and WebP. Many people use whichever format their camera or phone produces and never think about it again. But choosing the right format for the right situation can make a significant difference to image quality, file size, and compatibility. This guide explains each format in plain English and gives you a clear decision framework for choosing between them.
JPG (JPEG) — Best for Photographs
JPG (Joint Photographic Experts Group) is the most widely used image format in the world. It was specifically designed for photographic images — scenes with complex colour gradients, natural textures, and smooth transitions.
How it works: JPG uses lossy compression. It permanently removes some image data to reduce file size, focusing on areas where the human eye is least sensitive. The result is a smaller file that looks nearly identical to the original — but is not a perfect copy.
Use JPG when:
- Sharing or storing photographs — holiday photos, portraits, product shots
- Images will be displayed on web pages where file size matters
- You do not need a transparent background
- Storage space or bandwidth is limited
Avoid JPG when:
- The image contains text — JPG compression blurs sharp edges and makes text difficult to read
- You need a transparent background — JPG does not support transparency
- You are editing and re-saving the same image repeatedly — each save introduces additional quality loss
- The image has solid colours and sharp geometric shapes — logos, diagrams, illustrations
PNG — Best for Graphics, Screenshots, and Transparency
PNG (Portable Network Graphics) uses lossless compression — every pixel is preserved perfectly, with zero quality degradation. This makes PNG significantly larger than JPG for photographs, but the ideal choice for images where precision matters.
Use PNG when:
- The image contains text that must remain sharp and readable
- You need a transparent background — logos, icons, overlays
- The image has solid colours, sharp lines, or geometric shapes — diagrams, charts, illustrations
- You are taking screenshots — PNG is the standard format for screenshots
- You will be editing the image further and need to preserve all quality
Avoid PNG when:
- Storing photographs — PNG files are significantly larger than JPG for photographic content
- File size is a priority — PNG's lossless compression produces larger files than JPG or WebP
WebP — The Modern Choice for Web Images
WebP is a modern image format developed by Google specifically for web use. It supports both lossy and lossless compression, and crucially, it supports transparency. Most impressively, WebP produces files that are 25–35% smaller than equivalent JPGs and 20–30% smaller than equivalent PNGs — at the same visual quality.
Use WebP when:
- Images will be displayed on a website — WebP's smaller size improves page load speed
- You want the best file size to quality ratio for any type of image
- You need transparency but want smaller files than PNG provides
- The site audience uses modern browsers (all major browsers have supported WebP since 2020)
Limitations of WebP:
- Not universally supported in older software — some image editors and older apps cannot open WebP files
- Not ideal for print — use PNG or original camera files for print production
- Some email clients do not display WebP inline — use JPG for email image attachments
Quick Comparison Table
- Photographs for web: WebP (first choice) or JPG
- Photographs for email: JPG
- Photographs for print: Original camera file or TIFF
- Screenshots: PNG
- Logos with transparency: PNG or WebP
- Icons and simple graphics: PNG or SVG
- Web graphics without transparency: WebP or JPG
- Social media posts: JPG (most widely compatible)
- Images with text overlay: PNG
Converting Between Formats with Toolzilla
Toolzilla's Image Format Converter converts between JPG, PNG, and WebP entirely in your browser — no server uploads, no account required. You can also control the output quality using the quality slider, giving you full control over the file size versus quality trade-off.
Common conversion scenarios:
- PNG to JPG: Reduce file size for sharing or email when transparency is not needed
- JPG to PNG: When you need to add transparency or are embedding the image in a document that benefits from lossless quality
- Any format to WebP: For web use, converting existing JPGs and PNGs to WebP can significantly reduce page load times
- WebP to JPG or PNG: For compatibility with software that does not support WebP