Vector vs. Raster Graphics
A vector graphic describes shapes mathematically through points, lines and areas and stays sharp at any size; a raster graphic consists of a fixed grid of coloured pixels and becomes blurred when enlarged. Logos, icons and illustrations belong in vector form, whereas photographs always come as raster images.
In practice
Typical vector formats are SVG for the web and EPS, AI and PDF for prepress; typical raster formats are JPEG, PNG, WebP and AVIF. Insist on a vector file whenever a logo is handed over, because without one the logo has to be redrawn for vehicle livery or signage, which costs money and changes the result. SVG is a W3C-standardised, XML-based language for two-dimensional vector graphics. A leanly drawn SVG is therefore usually only a few kilobytes and stays sharp at any resolution; illustrations traced with very many path points, by contrast, can end up larger than a photograph. Recolouring through the site's styling works when the SVG is embedded directly in the page – as a linked image file it does not. A logo rebuilt from a raster file is recognisable by soft, slightly wavy edges when magnified. Before passing vector files on, check whether licensed fonts are embedded in them, because the font then travels with the file and few font licences cover that. Type converted to outlines is uncritical, but it can no longer be edited.