This is one of the most practical things to understand about your logo files, because it's the difference between a logo that scales cleanly to any size and one that quietly breaks the first time someone needs it larger than expected.
Raster: built from pixels
JPEG and PNG files are made of a fixed grid of colored pixels. Enlarge them past their original resolution and the pixels stretch, producing visible blur or blockiness — fine for a web-sized image, a real problem for a banner or a sign.
Vector: built from math
AI, EPS, and SVG files store shapes as mathematical paths rather than pixels, so they scale to any size — a business card or a building wrap — with perfectly crisp edges every time.
Where each format is used
- SVG — ideal for websites: scalable, lightweight, and editable in code if needed.
- EPS / AI — the standard for print production and professional design software.
- PNG — fine for everyday digital use (email signatures, presentations) where a transparent background is needed but extreme scaling isn't.
- JPEG — the least useful format for a logo; no transparency support and raster limitations.
What to actually keep on file
Store the vector master file (AI or EPS) somewhere safe and permanent — it's the source every other format gets generated from. If you only have a JPEG or PNG of your logo, ask your designer for the vector original; you're entitled to it as part of a proper delivery.
The short version
Vector files scale infinitely without quality loss; raster files don't. Keep a vector master on file, and use raster formats only for everyday digital contexts where extreme scaling won't be needed.