Customizing Image Heigh in Hotspot in All New Captivate

I've used the hotspot widget and changed the image to the one I needed. The image height is smaller than the default image. There is no way I can increase the image height without making it look odd like I forgot to remove the white space above and below the image. I would like to adjust the image height as per the images I use. How can I do that? Could you please shed some light on that?