How do spacecrafts like Voyager 1 and 2 transmit pictures of space back to Earth? How do they receive flight instructions from such a long distance from earth?

The astronauts were given a thermoelectric power source (plutonium) because there would not be enough solar light to keep them moving in the same direction unless something stops them (Newtons law). NASA is receiving faint signals from the spacecraft, not pictures. Even if we send signals, the spacecraft will run out of fuel before it can change its course. The spacecraft has crossed the solar system and supplied information about the solar wind in that region.

Spacecraft like Voyager 1 and 2 transmit pictures of space back to Earth using radio communication. They have onboard cameras that capture images, which are then converted into digital signals. These signals are sent to Earth via radio waves. The spacecraft receive flight instructions from Earth using a similar method: commands are transmitted as radio signals from Earth-based antennas to the spacecraft's receivers. The onboard computer interprets these commands and executes the necessary actions.