Infinite keyframes help[MX]

I was wonder if this was possible…Im new to action script so this question might sound dumb…
Is there a action script code that will allow me make something in the key frame show through the whole movie…

For example
3RD frame I want a jpg image to show till the end of the movie…
The movie is 500 frames…
Can I put a code on the 3rd frame to tell it to show itself all the way to the end of the 500 frames…instead of clicking on the 500 frame and placing a key frame on it?

I looked around the forums and on google…found nothing on it…please help:hangover: