Image songs are considered an important part of an anime or dorama's success, as they often provide insights to a character that may otherwise go unexplored on the program itself. The series creators may also include details about a particular character's design stages and evolution, and on occasion even design sketches so fans can see for themselves how a character changed. There may also be comments from the seiyuus or actors on how they feel about playing their characters.
In addition, fans are known to buy image song albums based simply on the seiyuu or actor. An example of this is Megumi Hayashibara, a well-known seiyuu who has released many cds and albums over her career, many among them image songs of her characters.
A related sub-type is a character version, where a seiyuu or actor sings a song from the series as the character. A famous example of this are the various versions of Neon Genesis Evangelion's theme songs, redone by the seiyuus of Rei Ayanami, Asuka Langley Soryu and Misato Katsuragi. They are usually identified by a version tag at the end of the name (e.g. Cruel Angel's Thesis, Ayanami Version). Another example of this are the character versions of Hare Hare Yukai. The three main characters, Haruhi Suzumiya, Mikuru Asahina, and Yuki Nagato have their own versions of the ending theme, using the original music. However, the characters Kyon, Itsuki Koizumi, Ryoko Asakura, Kyon's Sister, and Eimiri Kimidori features remixed versions of the ending.
Similarly, a character song can also be a song about a character, but not necessarily sung by the character's portrayer. For example, while Mazinger Z's include songs about Kouji Kabuto and his friends, they are not sung by their seiyuu. Nevertheless, they still provide some insight into the character's persona.
Image songs are not restricted to anime protagonists. Antagonists such as Zechs Merquise, Master Asia, Sailor Galaxia, and some of the villans (such as Devimon and Dracule "Hawk Eye" Mihawk) also have their own image songs. In some cases, these are more interesting than those of the protagonists as they often provide the only glimpse into a villain's character.