Help me before i print some posters

Hi guys i’m going to print some video games posters & wallpapers but i want to know how to recognize when the poster size won’t have pixel if you know what i mean
Answer #1
It sounds silly.. but pretty much as big as you can reasonably find.
http://www.urban75.org/photos/print.html
Is a good reference.. Further down it has a “Quality vs file size” bit which is interesting.
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It also matters what paper you’re using – you can get away with something on matt paoer that glossy paper will show as crap, and canvas paper will let you get away with a lot more..