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.
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.
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.