They are commonly produced from scanned drawings or photographs. They can also be created with a paint program, like the one that ships with Windows operating systems. Vector images are based on mathematical equations. The computer stores the images not as information for each small area of the drawing, but as a series of mathematical equations. The file sizes are smaller, and you can group and ungroup these drawings in most vector programs.
Vector images can have irregular shapes, and the background shows around the edges.
If you place a vector flower image on a slide, in most cases, there is no background to cover up the slide's background. Most of the images in the Microsoft Clip Gallery are vector images. You can purchase both types of images, so consider the image format when buying clip art.