This image is inaccurate. It conflicts with the actual flag:
orientation of the harp - strings are vertical, should slope from upper-left to lower-right
the colour, shape and decoration of the harp are too rich, linear, and ornate.
the strings are white/silver but should be yellow/gold
See photo File:Irish Naval jack.JPG and the description on FOTW, which is one of the two stated sources for this image ([1] and [2]). Neither source matches the image. (Although it agrees with an archived version of the official naval website, that page was amateurish and is no longer live.)
A work made by an officer or employee of the Government or State of Ireland in the course of his or her duties, created before 1st January 1974; or
A work made by an officer or employee of either House of the Oireachtas in the course of his or her duties, created before 1st January 1974; or
A sound recording, film, live broadcast or live cable programme of the proceedings of either House of the Oireachtas created before 1st January 1974; or
A bill or enactment of the Government of Ireland made available to the public before 1st January 1974.