By Courtney Field Creative digital graphics

Types of graphics and examples There are a number of different types of graphics file formats. Each type stores graphics data in a different way. Bitmap, vector, and metafile formats are by far the most commonly used formats, and we focus on these. However, there are other types of formats as well-- scene, animation, multimedia, hybrid, hypertext, hypermedia, 3D, virtual modeling reality language (VRML), audio, font, and page description language (PDL).

Bitmap Formats Bitmap formats are used to store bitmap data. Files of this type are particularly well-suited for the storage of real-world images such as photographs and video images. Bitmap files, sometimes called raster files, essentially contain an exact pixel-by-pixel map of an image. A rendering application can subsequently reconstruct this image on the display surface of an output device. Microsoft BMP, PCX, TIFF, and TGA are examples of commonly used bitmap formats.

Vector Formats Vector format files are particularly useful for storing line-based elements, such as lines and polygons, or those that can be decomposed into simple geometric objects, such as text. Vector files contain mathematical descriptions of image elements, rather than pixel values. A rendering application uses these mathematical descriptions of graphical shapes (e.g., lines, curves, and splines) to construct a final image.

The difference between bitmap and vector

Metafile Formats Metafiles can contain both bitmap and vector data in a single file. The simplest metafiles resemble vector format files; they provide a language or grammar that may be used to define vector data elements, but they may also store a bitmap representation of an image. Metafiles are frequently used to transport bitmap or vector data between hardware platforms, or to move image data between software platforms.

Why use different graphic types Because different graphic types are better at doing different things. For example bitmap data are particularly well-suited for the storage of real-world images such as photographs and video images. Vector format files are particularly useful for storing line-based elements and Metafiles can contain both bitmap and vector data in a single file.

Image size and resolution and compression. IMAGE RESOLUTION: Resolution refers to the number of pixels in an image. Resolution is sometimes identified by the width and height of the image as well as the total number of pixels in the image. IMAGE SIZE RESOLUTION: The computer screen you are looking at right now is set at a particular resolution as well. The larger the screen, the larger you likely have your screen resolution set. If you have a 17" monitor, likely you have it set at 800X600 pixels. If you have a 19" screen it is likely set at 1024X768. You can change the settings but these are optimum for those screen sizes.

COMPRESSION: In addition to image size, the quality of the image can also be manipulated. Here we use the word "compression". An uncompressed image is saved in a file format that doesn't compress the pixels in the image at all. Formats such as BMP or TIF files do not compress the image. If you want to reduce the "file size" (number of megabytes required to save the image), you can choose to store your image as a JPG file and choose the amount of compression you want before saving the image