Credit card
Software works decently--only thing I would suggest is to utilize a prepaid card, so they can't keep dipping into your account if you stop using the service.
Not enough ratings yet to assess PicPic Social.
PicPic Social appears legitimate, with a few gaps. AppsHunter Legitimacy Score for PicPic Social is 73/100.
Based on 73 of 100 points across 7 verification signals from App Store and developer data.