Default Stock Gallery Collage Quality

Hey Guys!

I'm trying to make a collage using 3 photos in the stock gallery, I have made a few of them. I'm using all high quality photos to make the collage, however, when I make the collage, it shows up as very grainy on the phone and on PC. Any idea how to fix this?

Thanks!
VZW Samsung Galaxy Note 3
Stock Rooted