Error message for Zazzle Poster

I made my word art (this is the most awesome program for this, I tried about five others) and then hit the button at the bottom to turn my art into a product. I then clicked on "poster" which took me to Zazzle, where I got this message:

"We can't move forward 'til you fix the errors below:

This product contains some images which have been made larger than their original sizes and may be blurry or pixelated when your product is produced."

I am trying to make a 12x12 poster.

What should I do about this? Do I need to download it to my computer and convert it to another format or something?

Thanks so much for the help!!

Hello Anaya,

Could you please try to switch to another poster size and then switch back to 12x12? Does the error appear now?

To me it seems like a glitch on Zazzle.com site.