Which format for what.
JPEG
Photographs. Good compression, no transparency.
The right choice for almost every photograph.
PNG
Graphics with flat colour, logos, anything needing transparency.
Poor for photographs, where it produces enormous files.
THE COMMON MISTAKE
Saving photographs as PNG. That can be ten times larger than the same image as JPEG.
WEBP
A newer format producing smaller files than JPEG at similar quality.
Supported by all current browsers. Worth using.
SVG
Vector graphics: logos, icons, simple illustrations.
Scales to any size with no loss and tiny file size.
Note that SVG can contain code, so only use files from sources you trust.
WHAT TO DO PRACTICALLY
Photographs as JPEG or WebP Logos and icons as SVG or PNG Nothing as BMP or TIFF
FOR CONVERSION
Free tools convert between formats in bulk.
