The images appeared to show the pair on foot during a safari in June at the Gir National Park in western Gujarat state.
Officials at the park said they imposed a preliminary fine because "the cricketer flouted the rules".
Visitors to the park are not allowed to leave their vehicles.
Jadeja's photos were posted days after Gujarat forestry officials warned of the dangers involved in taking selfies with lions, following a number of attacks.
Wildlife officers say they will submit a final inquiry report to their superiors soon.
A.P Singh, chief forest conservator in Gujarat state, told AFP they "had instituted a probe and called Jadeja for a statement... but since he was not available, his father-in-law Hardevsinh Solanki gave a written statement on his behalf" and paid the fine for him.
Jadeja, 27, was part of India's team for the recent World T20 tournament.
A photo posted on Jadeja's Instagram account showed the cricketer pointing to a pride of lions behind him, with the caption, "Family photo, having good time in Sasan (Gir) #rajputboy #wearelions".
A second photo posted to the cricketer's account showed him and his wife, Reeva, with a lion looking on in the background.
The national park at Gir is the only place where Asiatic lions remain in the wild. The animals, which are slightly smaller than African lions, were listed as endangered in 2008.
Indian cricketer Ravindra Jadeja has been fined 20,000 rupees (Â£229; $300) after posting photos online of him and his wife posing in front of endangered Asiatic lions.