Side image
From VNDev Wiki
A side image, side portrait, or textbox image is a character picture that is displayed on the textbox. They are usually head-only or busts and the textbox is usually designed specially to display these images.
Many games only use side images for characters who are not shown on-screen or for internal reactions. (example uses: An off-screen character talking, the MC only being displayed in CGs and side images, or a character's private thoughts/reactions that they keep hidden from everyone else in the scene). Alternatively, side image sprites may be rendered in a different style from the screen sprites. (ex: Side image sprites are chibi, or screen sprites are 3D models.)
