Custom label

You can customise marker pop-up labels (balloons) by setting custom content (texture) to them. Basically you just extend abstract class Label, write own code to drawMarkerLabel() method, and use this.

See source of the basic default label with 1 or 2 lines DefaultLabel.java to have idea about API of Label and how this can be implemented. Like in sample, it is probably easiest to use Bitmap canvas where texts (and possibly graphics) is painted.