Since Flash is usually about graphics and manipulation of graphics, publishing just the swf means that the movie will resize to the entire browser window.

If someone has a screen resolution of greater than 800x600 the animation will slow down considerably. Alpha fades are jumpy, animation is too.

Also, bitmap images created at a smaller size will stretch and become pixellated.

The site will therefore look awful to a heck of a lot of people.

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Sualdam