PNG Image Quality Degrades When Pasted into Illustrator

I am adding a PNG image to an existing artboard. when i copy and paste it, the quality of the images are all degraded. can you help correct what is now happening? please see screenshots. one is illustrating the PNG file opened and the other is a screenshot of the image copied and pasted in ai. things were working fine a little while ago. then things went bad. i even restarted my laptop thinking it would solve the problem, but it did not resolve the problem.