Image Colors Changed After Editing in Preview or Pixelmator

[lilaundgelb]

Recently, images that I edit in Preview (e.g., by rotating the image) or Pixelmator (e.g., by painting on an image or applying a filter) have something screwy happen to the colors. I'm attaching two examples: the image on the top left was rotated twice then saved, producing the image on the bottom left; I used a paintbrush tool on the image on the right.

This doesn't happen when I edit an image using GIMP, Seashore, or SketchBook.

I'm running Yosemite (although this started happening when I was using Mavericks).
Motherboard: Gigabyte GA-B75M-D3p
Processor: Intel Core i5
Memory: 16GB
Video Card: NVIDIA GeForce GT 610 (Asus)

 

[jmain]

I get this same issue. Did you ever solve it?