Smooth image at first,then all of a sudden jaggy?

I’ve seen it happen before to one of my images on another swf file. Didn’t change a thing on the image, saved my fla as another version for back up , then suddenly my image is jaggy (a little pixelated), why does that happen? I didn’t change any parameters at all.

read that

I forgot to mention that I did.
It didn’t help.
BTW there was no crack, it just didn;t come out as smooth as it used to be.

I found a workarond, not sure why it would even change from smooth to jaggy on it’s own…
I re-imported another png to replace it( the now jaggy one). The original pngI had in the library was bigger than I wanted it on the stage and I scaled it down previously. Worked fine for a while then went jaggy.

THIS time BEFORE I re-imported the png, I made sure it was to the EXACT scale I wanted it on the stage. Then it looked smooth once again.

Hope this helps someone else.