Image file format

An image file format specifies how digital image data and related information are encoded and stored. Formats differ in structure, supported color information, compression, and features such as transparency or animation.

Raster graphics: Images represented as grids of picture elements, or pixels. Most image file formats encode pixel grids, though some also store other data.
Raster image file structure: The arrangement of headers, metadata, and encoded pixel data in a raster image file. Headers and data chunks tell software how to interpret an image's contents.
JPEG: A widely used image format whose common photographic encoding uses lossy compression. Its compact photographic files make it common in cameras and online images.
BMP file format: A raster image format associated with bitmap files, often storing pixel data with little or no compression. Its straightforward storage contrasts with formats that prioritize smaller files or richer features.
Vector graphics: Images represented by geometric shapes and paths rather than fixed grids of pixels. Vector formats describe scalable shapes instead of storing a fixed pixel grid.
Lossless compression: Compression that allows the original data to be recovered exactly. Formats using it preserve every encoded pixel value after decompression.
PNG: A raster image format supporting lossless compression and alpha transparency. It suits graphics that need crisp edges, transparency, or exact pixel values.
JPEG 2000: An image coding system based on wavelet compression, with both lossy and lossless modes. It offers different compression tools from the discrete-cosine approach used by conventional JPEG.
Color model: A mathematical system for representing colors as sets of values. Formats specify how stored color values correspond to visible colors.
Lossy compression: Compression that reduces file size by discarding information that cannot be exactly restored. Many image formats trade some fidelity for smaller files.

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