one small problem in Pages

For school, i need to make a brochure and for that im using Pages. As i am putting im images in, it seems to be making shadows on the edges, it makes the look of the images appear to "stick out" rather than just being flat on the page. I have many pictures to add to my brochure, and with the shadows on the images, it really makes my brochure look very strange.

Is there a way i can take the shadows off?

(you can notice it on the image i linked)