Here are three animated logos in a single Flash file (also know as a SWF).
The total size for all three animations is an astonishingly small 22KB
... which is less than a single, low quality jpeg image!
The images in these animations are vector graphics created in Adobe Illustrator,
or text objects created inside of Flash. Since the images are
not pixel-base, the animations are entirely scalable,
without distortion to the quality of the image.
Click here to view a resizable version of this animation.
The animation will open in a new browser window.
As you resize that browser window the animation will resize itself
to match the current dimension of your browser window.
You'll see that the fidelity increases as you make the animation larger,
whereas a pixel based animation would deteriorate when enlarged.