My random translations of the photo captions, clockwise from top left are:

• Positron II
• RS
• Tourney
• Positron II

• Publisher: New Cycling
• Document: New Cycling May 1981 - Derailleur Collection
• Date: May 1981
• Derailleur brands: Shimano
• Derailleurs: Shimano Tourney, Shimano RS (RS12), Shimano Positron II