I know that you have all seen graphics on the web that look jagged (pixellated) around the edges this is because computer monitors use essentially a grid (kinda like graph paper) of pixels (a contraction of "picture element") to display the colors of a graphic. These pixels can only hold one color filling the entire (very tiny) square. For a good example of this go to your paint program that came with your operating system and paint a little and zoom in really really close.

One way to avoid the "jaggies" is to antialias your graphics. Antialiasing is the smoothing or blurring of the images edges. Most painting programs can now support antialiasing. Antialiasing can include adjusting pixel positions or setting pixel intensities so that there is a more gradual transition between the color of a line and the background color. In other words anitaliasing blurs the edges of the image so that there isn't a harsh transition between the image and the background. If for some reason your program does not support antialiasing try blurring the image slightly.

NOTE: Graphics cannot be antialiased in indexed color (.gif image) mode. Indexed color mode defines a set number of colors (a palette) that can be used in the image and antialiasing essentially creates colors in-between the colors of an image and it's background. In other words if you have a .gif file and you want to add something to it and want it antialiased you first must convert it to RGB (red,green,blue) mode. Once you have made the necessary changes you can then convert it back to indexed color mode and save it out as a gif.

-- Christine