You shouldn't use jpg for texture, use one of the other proper formats instead (see manual). The "problem" you've encountered with png is its alpha channel, either change the png from 32bit to 24bit or make sure you render the model in solid mode (right now it is rendered in the transparency pass).
"Falls das Resultat nicht einfach nur dermassen gut aussieht, sollten Sie nochmal von vorn anfangen..." - Manual
