Some TV-s may have a preset for for computer. My parents have a TV from Phillips, and colors from PC were awful. We than changed a preset to one saying "computer" and everything got just fine.
Another issue to keep on mind may be that HDMI can be operated in standard or enhanced mode. Standard mode is broadcast and uses only a part of the tone scale (16-232 I guess). So if computer outputs enhanced HDMI and TV is set for standard to steep contrast will result.
As a side note, I used Fotomagico, but I'm moving away from it and started using Final Cut Pro X instead. The main reason is that I am concerned about long term stability of Fotomagico file formats. I have stuff that won't play any longer. Also, if I export Fotomagico slideshows as movies the results are not very impressive. But I still use Fotomagico from time to time, just not for stuff I want to be around 'for ever'.
By adjusting colors and contrast on your TV. TVs are typically sold with way too high contrast and saturation.