Vector and Raster Images
Step 1
Two Types of Digital Image Files
Vector Images
Vector images are made of shapes filled with color. The shapes are mathematically defined as curves and lines between points. With vector images the resolution is defined by whatever output device the image is being displayed on, such as a monitor or a printed piece of paper. Monitors and printers are raster devices and do have a set resolution, the data in the vector image file is temporarily converted to a raster image to match the current output device every time the file is opened. The rasterized version of the image is thrown away when the vector image file is closed and the next time the vector file is opened, the image is temporarily rasterized anew to match the resolution of the new display device, whatever it may be. Vector images do not have a set resolution coded into the image file, because of this, vector images are said to be "resolution independent".
no matter how big the curve gets.
Raster Images
Raster images are made of tiny blocks of color called pixels that are stacked in a grid to form a image--much like a mosaic of tiles with really tiny tiles. The resolution is defined when the image is created and cannot be made any larger without some loss in quality. Also, if the image is reduced in size then saved, extra pixels are thrown away and are lost from that file forever.
