Is my neon tetra pregnant? ( Pictures )?

Yes, it looks like she if full of roe (eggs). Breeding tetras is not easy. Soft acid water pH6.0 is needed and the temperature should be lowered quickly to 65-68. Put the whole school into the prepared breeder tank without acclimating. Keep in a dark place for several hours. Remove the whole school and gradually warm the tank to 78-80. The fry are almost invisible and will start showing up in 48 hours. Feed when egg sac is gone.