While there are many photos of the twins as babies and young children on the show, there are no "real life" photos of the twins publicly available. This is because the role of Nicky and Alex was played by several different sets of twins during the show's run.
It's important to remember that the twins were very young when they filmed the show, and their privacy is important.
You can, however, find plenty of photos of the twins in character on the show, which can be easily found online.