An image recording system includes an image supply apparatus compatible with a first image recording service standard, an image recording apparatus compatible with a second image recording service standard, and a conversion apparatus connected, as a pseudo image recording apparatus compatible with the first standard, to the image supply apparatus via a communication medium compatible with the first standard and connected, as a pseudo image supply apparatus compatible with the second standard, to the image recording apparatus via a communication medium compatible with the second standard. The conversion apparatus converts a command received from the image supply apparatus into a command complying with the second standard before transmitting it to the image recording apparatus, and converts a command received from the image recording apparatus or event information relating to an image recording process into a message complying with the first standard before transmitting it to the image supply apparatus.