House electrical panel box question
 

can someone tell me if this is 100amp or 200amp service?

I can't read what size the main breaker is. It should be a 100 amp but the important thing is that it is fed by at least a #2 gauge copper wire. It has to be at least that size to carry 100 amps. Main breaker is supposed to be sized to trip before the wire burns up. #2 copper is good to carry 100 amps thus can have a 100 amp breaker. I have seen where somebody has put a 100 amp breaker on smaller wire, that does not make it a 100 amp service. Wire could burn up before breaker trips.

The main breaker is 100 Amp, so.....

100 amp 220 volts

Yes the main breaker is 100 amps and is a 2 pole (double) breaker which is good to give 220 volt. Is there a breaker at the meter outside? Is it 100 amp? There is wire feeding into the main breaker in your picture from the service (meter) outside. That wire needs to be at least a #2 size copper wire or a #1 size larger) aluminum wire to be able to carry 100 amps of current per code. The only way to verify this is to remove the cover and check what is written on the side of this wire. Size will be written on the side of the wire itself. If you are not qualified or able to safely remove this cover yourself (there are electrically energized parts behind the cover) and do this you may need to hire an electrician to verify this for you. If you touch the wrong thing when the cover is off it can kill you.

I am telling you what it takes to actually be a 100 amp service.

The breaker is the right size but the correct wire size is part of the system. If it was installed by a licensed electrician everything should be correct for a 100 amp service. Odds are yes you have a 100 amp service.