Blurry images
 

Hello,
images in Omnigraffle are displayed extremly blurry. I tried to add images in different ways - pasted from the clipboard, dragged an image (png24) from the desktop, defined a new source from an existing image on the document via inspector. Result is always the same: the image is extremly blurry. I use OG 5.4.2 on OS X 10.8.2. Am I doing something wrong? How can I fix it?

Screenshot: [IMG]http://speicher1.de/blurryOmniGraffle.png[/IMG]