The Hubble telescope was built with a purpose. It was for the purpose of finding out what the value of the Hubble constant. One of the puzzles in cosmological discovery at that time was that the Universe was expanding. Cosmologists after the Copernicus time understood that the universe was dynamic in nature, and this meant that the universe was seen to be existing based on some form of a dynamically changing substance Vesto Slipher’s measured the radial velocity of nebulae by using the works and findings on the distance to the galaxies that was formulated by Edwin Hubble. Hubble is in fact credited with finding the expansion of the Universe, although similar findings of Georges Lemaitre and H. P. Robertson were seen to precede him. However the purpose for which the HST was created and the purpose with which it was used with the discovery of the Cepheid variable stars in M31, actually connects Hubble and his discoveries more to the point than others.
The image is that of the Cepheid variables in the M100, and as such it is a part of the galaxy. The image was used efficiently by means of the HST. The HST program as such remains open for scientists to use.
The Hubble site.org was the source used extensively. This is the official site to understand the technology and more current and past works associated with Edwin Hubble and his findings. The work is part of the Office of Public outreach that was designed by for the Baltimore and the Washington area. The site is produced and is updated by the Space telescope Science Institute OPO (Hubble Site, 2015).