Change image source in instance symbol

Well, I need a little slideshow of images, the code for mouse events (click, mouseover, mouseout, etc.) is the same for all images, then I create a symbol with one image inside for this, and drag&drop instances to stage, but now I don't know how change the image source of other symbols. In design time, when right click over any symbol instance only edit symbol it's possible (not single instance), and I don't know if is possible to change the image source of any symbol instance by code.

Thanks.