Raster file extensions include common formats like .jpg, .png, .gif, .tiff, and .bmp.
Understanding Raster Files
Raster files, also known as bitmap images, are composed of a grid of tiny squares called pixels. Each pixel is assigned a specific color, and together, these pixels form the complete image.
As the reference states, popular types of raster files include JPEG, PNG, and GIF images. A key characteristic of raster images is that their pixel number is fixed. This means that when you try to resize a raster image, especially to a larger size, the fixed pixels must be stretched, which can cause the image to become distorted or blurry.
Common Raster File Extensions
Various file extensions denote raster image formats, each with different characteristics regarding compression, color depth, and support for transparency or animation.
Here is a table listing some of the most common raster file extensions:
| Extension(s) | Full Name | Description |
|---|---|---|
.jpg, .jpeg |
Joint Photographic Experts Group | Widely used for photographs; employs lossy compression to reduce file size, which can slightly reduce quality. |
.png |
Portable Network Graphics | Supports lossless compression and transparency (alpha channel), making it ideal for web graphics and logos. |
.gif |
Graphics Interchange Format | Supports animation and transparency, but is limited to 256 colors, making it suitable for simple graphics and short animations. |
.tiff, .tif |
Tagged Image File Format | Often used for high-quality images, especially in publishing and printing; supports lossless compression and high color depths. |
.bmp |
Bitmap | An uncompressed format, resulting in large file sizes; less common on the web but sometimes used for simple icons or graphics. |
.webp |
Web Picture format | Developed by Google, designed for the web, offering both lossless and lossy compression, and supports animation and alpha transparency. |
.psd |
Photoshop Document | Adobe Photoshop's native format; can contain layers, masks, and other editing information. |
.raw |
Raw image formats | Unprocessed data directly from a digital camera's sensor; requires specific software to process. Extensions vary by camera brand (e.g., .cr2, .nef, .arw). |
Understanding these extensions helps in choosing the right format for different purposes, whether it's for web display, print, photography, or graphic design.
