Enlarge picture in footer

Hi, I’m using the Amadeus theme and I’ve added a picture in my footer using the text widget. The image’s original size is 651 x 62px, but once I add it to the footer, it is re sized to 350 x 33px. Using “width= height=” I am able to make the picture smaller than 350 x 33px, but not any larger. I assume there is a limit somewhere that I need to change. But I can’t seem to figure it out. Any help is appreciated, thanks!