I have gapped small teeth. Is Invisalign a good option? (photos)

Invisalign is great to close gaps. In your case it looks like your teeth are slightly too small. You have worn down the teeth and flattened the, Mathis is usually due to grinding the teeth and a better bite would help this. It looks like Invisalign would help to give you a better bite but the gaps will probably still be left between the teeth after orthodontics. These gaps can be closed with veneers after you are finished with the alignment. 

Your teeth appear to be very narrow compared to the amount of space you have in your arch. I think veneers will give you a better long term result. If you do Invisalign and move some of these teeth closer together you will still need some veneers after treatment to close spaces. I would jump the Invisalign step and move forward with veneers.