I am looking for a software to simply place dots on specific points on an image. For a concrete example, I have an image taken on a microscope with a 5x lens and I have to set a coordinate system with the origin at its center, and it's height ranging from -54 to +60 (bottom to top) and its width from -90 to +90 (left to right). Having done this, I have to set dots on specific coordinates relative to this new coordinate system, because these new dots is where data with a 50x lens was taken. Doing this I will be able to say "I took data from here, here, there and also there". How can I do this?