Wrong colors after compression

There are a handful of pictures that after I upload them and they get compressed, the colors go wonky. The image I have linked is the compressed version. The two moons on the left are supposed to be blue and the text should be white but everything is pink and purple.

Is there anything I can do to avoid this? It doesn’t happen all the time but when it does, it totally changes the look of the artwork I’m trying to demo.

The page I need help with: [log in to see the link]