Upfront - unable to change gallery images

Hi,

I have been trying to change all these pixelated images on the gallery page of the Spirit Theme, however after selection from my media gallery they re-sort the existing gallery images and do nothing.

http://demo.tradr.com/gallery/

My pictures are still uploaded here:
http://demo.tradr.com/files/2015/01/tropical-white-sand-beach.jpg
http://demo.tradr.com/files/2015/01/tropical-resort-with-pool.jpg
http://demo.tradr.com/files/2015/01/tropical-massage-1.jpg

Cheers,

Johnny