Super Blurry Images in Popup

Hey there! I have a website with a bunch of team members listed out: http://www.healingelements.org/teachers/ and for some reason the initial image is clear enough, but when you click on the item and open the popup to read more about the team member the image is incredibly blurry.

I've searched everywhere for a setting for this, but have yet to find anything :/

If you have any ideas as to how I can fix this I would be greatly appreciative! Thanks in advance.