JPEG: best for photographs
Lossy compression, no transparency, small files for photos. Supports 16.7 million colours. Compression artefacts visible at low quality. Best for: photos, screenshots of real-world scenes, social media images.
PNG: best for graphics
Lossless compression, supports transparency (alpha channel), larger files. Best for: logos, icons, screenshots with text, graphics with sharp edges, images that need transparency.
File size comparison
A typical photograph: JPEG at quality 85 might be 200KB, PNG of the same image could be 1-3MB. A simple graphic with few colours: PNG might be 15KB, JPEG could be 30KB with visible artefacts around text edges.
When to use JPEG
Photographs and complex images. Social media uploads (most platforms re-compress anyway). Email attachments where file size matters. Web pages where loading speed is critical.
When to use PNG
Images with transparency. Logos and brand assets. Screenshots containing text. Graphics that will be edited further (lossless means no quality loss). Pixel art and images with sharp edges.
Converting between them
ToolPouch converts JPEG to PNG and PNG to JPEG in your browser. When converting PNG to JPEG, transparent areas become white (or a background colour you choose). When converting JPEG to PNG, no quality is gained - the lossy compression from JPEG is permanent.