Rasterformate

Rasterformate are digital image file formats that store image data as a two-dimensional grid of pixels. Each pixel holds color information, usually as multiple color channels and a defined bit depth. Raster formats are contrasted with vector formats, which describe shapes and lines rather than fixed pixel values. They are the most common format for photographs and web images.

Raster images are resolution-dependent, meaning scaling the image up can cause blur or blocky edges because new pixel values must be interpolated. They use compression to reduce file size, which can be lossless (preserving all original data) or lossy (discarding some data for smaller files). Lossless formats are preferred when exact fidelity is important; lossy formats may offer much smaller sizes for photographs at the cost of some fidelity.

Common raster formats include JPEG, PNG, GIF, TIFF, BMP, WebP and HEIF/HEIC. JPEG is widely used for photographs due to its adjustable quality and small file sizes, but is lossy and not ideal for images with sharp edges or text. PNG is lossless and supports transparency, making it suitable for web graphics. GIF supports simple animations and a limited color palette. TIFF is versatile and can store uncompressed or compressed data suitable for professional workflows. BMP is a simple, often uncompressed format. Modern formats like WebP and HEIF/HEIC offer improved compression and quality. RAW files from cameras store sensor data and require processing before display; they maximize post-processing flexibility but are not display-ready.

Choosing a raster format depends on quality requirements, color fidelity, transparency needs, editing workflows, and platform support.