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What are Raster Files?

Raster files represent images as a finite two-dimensional grid of pixels, so the available detail depends on the image resolution. Each pixel stores color and may include transparency or other channel data.

How Raster Files work

A raster file combines a finite pixel array with rules for interpreting its channels, sample depth, row organization, and often compression. Containers differ substantially: some preserve alpha, profiles, orientation, layers, or multiple frames, while others expose little beyond raw samples. Raster assets enter media workflows at capture, rendering, compositing, and delivery, where dimensions and color interpretation must be normalized without needlessly decoding and re-encoding lossy sources.

Key facts

  1. Uncompressed pixel memory is determined by dimensions, channel count, and bytes per sample, not by compressed file size; a small download can expand into a large decode buffer.
  2. Pixel dimensions alone do not define physical print size. Resolution metadata supplies an intended pixel density, and applications may ignore or reinterpret that metadata.
  3. Orientation may be metadata rather than stored pixel order. Removing metadata without first normalizing the samples can leave a delivered raster rotated or mirrored.

When Raster Files matter

Choose raster data for photographs, screenshots, and textures whose appearance is naturally pixel based. Enlarging beyond the source resolution cannot recover missing detail and may expose interpolation artifacts.

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