You should be able to do this using the shapepar package, but would need to state the outline of the image shape by yourself. Note that as far as it concerns (La)TeX all images are rectangles and the fact that the outer margin is white or transparent doesn't matter to it. However, a image editor like Gimp, Photoshop etc. might be used to export the required coordinates required for shapepar. Anyway, it is connected to some effort.