PNG and Opera?

I have a site im trying to sort out and the navigation is png and the main header is png, the site has the unit png fix in it for IE but the images dont show up in opera and the font sizes are in em as well and they are massive . In ff and safari the site is lovely but in opera its Poo. please advise

Thank you

Opera will often apply IE fixes even when doing so breaks the site. Any IE fixes you apply should have code added to them to check that the browser isn’t Opera.