That is some limitations in the freeimage loader in such cases, i'm just using the raw 32bit texture data it provides. My guess is that it doesnt support palleted png's.

You can write you'r own loader by extending the TPHXTextureManager class if you have code to load PNG-8 with palette functionality.

It doesnt matter if the imageeditor show the images incorrectly if you have working code for loading the images in the game. The image format in phx just appends the original image to the new file and thus there's no format change.