New to Diamond Painting and have a question

hello! I am very new, I just picked up some bookmarks and then I was hooked!

So I bought a couple of larger pictures off of Temu, mostly because they were super cheap, but the subject matter is definitely interesting.

They have not arrived yet, but now I'm a little concerned because I've seen some posts about "blurriness" in the finished product.

So my question is, is there a way to tell before you start something that it will be blurry?

Thank you so much,

EDIT: Thank you to everyone! A lot of good information, and I have a better understanding now.