Decal not appearing when ray tracing in Autodesk Inventor 2017

Whenever I try to render/ray-trace this inventor file, the decal does not display at all. What I do is this: I apply the decal to a 24x24" aluminum sign body, then extrude numerals on top of that. The numerals display properly, but the decal does not. The decal is a png file. I am using Inventor Professional 2017. Also, when I upload the files to GradCAD, the ipt and stp thumbnails do not display properly on the website, either (with regard to the GrabCAD display issue, I've had this problem with some of the other stuff I've submitted, but in this case, nothing is displaying properly except the pngs). Is there a problem with the settings on my computer, or a problem with the software itself? Thanks in advance.