Drop4Side is a script for 3ds Max, built by Dong-Wook Kim, that creates a four-sided image plane inside the viewport. Alongside the plane, it can create a height box, giving you a pair of objects to work with directly in the scene.
The image plane comes with its own set of controls: you can select it, hide it, freeze it, and adjust its opacity. The height box has matching controls for height, hiding, and opacity, so both elements can be managed as you work.
Installation is handled by dragging the .ms file into the 3ds Max viewport. Once loaded, the tools appear under DW tools in the Category list via Customize, then Customize User Interface. Drop4Side was created by referring to Christoph Bulter's script "Drag & Drop Reference Images." It runs on 3ds Max 2022 or higher and is listed here as free.