So... I have added a button to my nav bar in the interface editor, however when I set the image I simply get a blue box. The images are the correct size, however they do not sho
The problem is your image. The image isn't shown as-is. The image is used as a mask to generate the actual image. Only the alpha channel of the image is relevant, not any of the colors.
The simplest solution for your particular image is to remove all of the white from the image and make those parts fully transparent.