With the new 5.2 Release (5.1 has not been tested) the V3d_View::SetBackgroundImage function works not as supposed.
The Background image is only displayed, if the SetBackgroundImage function has been called, when there is no object display. If one object is displayed in the viewer (e.g. Trihedron), the background will be black.
Yesterday, I digged through the whole code of the OpenGL driver, but I couldn't find the reason.
Please help me - or at least - confirm that this is a bug !