The primary image released comes from ACS/HRC data from the HST proposal 10867: R. Kirshner (Harvard-Smithsonian Center for Astrophysics).
F435W (B), F555W (V), and F625W (R)
This image is a composite of many separate exposures made by the WFPC2 and ACS instruments on the Hubble Space Telescope using several different filters. Three filters were used to sample broad wavelength ranges. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are:
Blue: F435W (B)
Green: F555W (V)
Red: F625W (R)