Sup /wg/

So Photobox are doing a deal on real large posters, and I was gunna get 5 1920 x 1080 images printed on either 45'' x 30'' or 40'' x 30''.

When i upload the images, it says they're low quality. Now, I don't wanna shell out for these posters for them to look grainy and shit, so any recommendations?

Images attached.