Weird spots on pictures

Thanks for the responses

Im a bit cautios performing a 'wet' cleaning of the sensor, as you said it might not be that hard.

But i dont have really steady hands so im rather afraid i do more harm then good:(

But like you say, it might be better for me to learn this, also if i get dust on the sensor on holliday for instance, when i cannot go to a shop and let someone clean it.

Thanks for the advice!