ardhuru, Joe S., thanks for your help

Those were my thoughts also, i just dont understand why only 2 ports ( without resistor ) give a diferent result and the other 4 ( also without resistors ) light up just fine.

Without the resistor the leds light up brighter as expected, but these 2 ports ( also without the resistors ) just barely light up .

Maybe there is something in this pic's hardware to produce this behavior.