Data Transfer : Graphics Files

There are three standards formats used for storing graphics files. They are :

• Bitmap File : Bitmap files store images by remembering the colour of each dot (known as a pixel) used to make up the image. Bitmap files usually take up a lot of storage space. They are a standard in the sense that most graphics packages can save data as a bitmap file. However computers using different operating systems have different formats for bitmap files.

• GIF File : A GIF file is a compressed graphics file. Instead of storing information about individual pixels in an image a GIF file stores information about sequences of pixels. GIF files take up less space than bitmap files to store but usually take up more space than JPEG files. An image saved as a GIF file will look exactly the same as the original image.

• JPEG File : JPEG files are highly compressed graphics files. JPEG files can store an image in a very small space. However some detail can be lost from an image when it is stored as a JPEG file.

The GIF and JPEG standards are particularly important. Any image that is to be displayed on the Internet must be stored in one of these two formats.

GCSE ICT Companion 04 - (C) P Meakin 2004