Problem finding copy of photo with best resolution

I had a photo accepted for an Art Show that I tried to print on a canvas. The first two photos that I had accepted and tried to develop on canvas were beautiful. This one has distorted colors and poor resolution, yet the photo itself was beautiful. Could you explain why this is? Is it true that I could have completely messed up the resolution simply by putting my signature on it as a watermark?

Or Could it be because I took the photo in live mode? I'd appreciate any advice! I had the photo accepted because I just submitted it as a photo, rather than taking a picture of the final canvas product. I now need to find the best way to actually present the photo in a show, or find a copy with better resolution .

Thanks!