This is a E27 socket to illuminate litophanes. It was designed to keep the E27 socket in place. This is achieved by using the friction caused by the remains of the support. IMO the lamp socket stand is suitable for litophanes with a height of about 120mm - 160mm, but it's up to you. The example shown in the pictures (dogs) is a 130mm tall litophane. I think the E27 lamp illuminates this litophane pretty nicely.

If you're able to edit objects in FreeCAD you can adjust the height of the stand to fit your litophane using the FreeCAD-document which I also uploaded.