Raster Image

A raster image represents a picture as a grid of pixels, each carrying color information. Also called bitmap images, common formats include PNG, JPEG, GIF, BMP, and WebP. Raster images excel at complex color reproduction like photographs and enjoy universal device and software compatibility.

PNG is the most common raster format for QR code export. Its lossless compression preserves the sharp black-white module boundaries that JPEG's lossy compression would blur. JPEG introduces compression artifacts at module edges that can reduce scan accuracy, making it unsuitable for QR codes.

The main weakness of raster images is quality degradation when scaled up. Enlarging beyond the original resolution stretches pixels, creating jagged edges (aliasing) and blur. A QR code generated for a business card will fail to scan if enlarged to poster size. To avoid this, either generate at sufficient resolution for the intended use, or use SVG (vector format). SVG defines shapes mathematically, so it never degrades regardless of scale. The practical standard is SVG for web display and high-resolution PNG for print.