I have this problem that I dont understand the answer to at all. Could you please help me with my misunderstanding?
So as far as I know, when image charges are used you do superposition and take one charge then find its mirror charge with respect to the grounded plane with potential 0V. Then you place it and after that repeat for the second charge. If I would follow my own method I would basically end up with the same image but with charge -2q below and +2q above at the same location as previously. What am I doing wrong and what should be done here instead?