Vector vs raster — what is the difference?

Every digital image is either a raster (pixel-based) or a vector (math-based). Knowing which is which solves most 'why does my logo look blurry?' problems. Here is the plain-English version.

• Raster graphics: A raster image is a grid of colored pixels. Each pixel has a specific color, and the image has a fixed resolution. Common raster formats include JPG, PNG, GIF, BMP, TIFF, and WebP.
• Made of pixels arranged in a grid
• Has a fixed resolution (e.g., 1920x1080)
• Pixelates or blurs when scaled up
• Best for photographs and screenshots
• Vector graphics: A vector image is described mathematically using points, paths, curves, and shapes. There are no pixels — the image is recomputed every time it is rendered, at any size. Common vector formats include SVG, EPS, AI, PDF (when vector content), and DXF.
• Made of mathematical shapes and paths
• Resolution-independent — scales infinitely
• Best for logos, icons, illustrations
• Editable shape-by-shape
• When to use raster: Photographs, complex natural imagery, screenshots, and anything where you need exact pixel-level color information.
• When to use vector: Logos, icons, brand marks, illustrations, charts, diagrams, signage, packaging, and anything that needs to scale or be edited later.