Rays around stars in images taken outside the atmosphere

[SkylarkM]

My apologies for a question that has undoubtedly been answered; I couldn't find the answer when I searched, however.

Many of the Astronomy Picture of the Day images have rays coming from some of the stars but the descriptions imply that the image was taken from a beyond-the-atmosphere source, such as Hubble. I thought that rays are a result of atmosphere distortion and only occur with images taken from underneath the atmosphere, so should I assume that these images have been manipulated in some way? Or, is my assumption incorrect?

[geckzilla]

Here you go.