Why is this happening?

I hope someone knows how to fix this because I can’t figure it out. For some reason, the last .jpg in line for my sliding navigation always ends up looking like the ‘pixel stretching effect’ as you can see in the .swf(it is the first to come up and linked to button 4)
The first three images work fine, and I’ve used four different jpg’s for the last one in the row. The image looks fine in the fla. I’ve used a colored rectangle with some text and that came out fine. Any ideas on this one?

here’s the swf

and here’s the fla