Holoshop

"For the last time, no I will not make a nude hologram of that pretty Twi'lek server for you!"

- Trak Nar, to Darth Panda

Holoshop was an incredibly expensive holography program that most users ended up acquiring with more unorthodox methods, which included accessing the HoloNet to download the program from others who were willing to risk Imperial persecution prosecution.

Purpose
The reason the program was so popular and, thus, expensive and often pirated was that it allowed for the production of holographic art with relative ease. Users with enough talent could create nearly-identical holographic representations of either themselves, famous people, or interesting objects. A subset of Holoshop users (the more perverted set, mind) specialized in making holographic depictions of the aforementioned famous persons in compromising positions. For example, a Rebel sympathizer on Coruscant was arrested and sent to Kessel for creating and distributing an animated hologram of Grand Moff Wilhuff Tarkin engaging in a Wookiee-Nookie "gang-bang".

Other amateur holographers engaged in the not-entirely-shunned industry of holo-pornography (this, obviously, being related to the famous "Wilhuff Moff Muff" scandal). These pornographers, however, were tame by comparison, and typically limited themselves to creating scenes of, for example, "hawt Zeltron on Twi'lek lesbian action". Such holofilms were popular on more isolated worlds, where the denizens would rarely, if ever, get to meet an individual of another species.