Photo resizing issue

Hi! I am trying to make an AR photo library, so literally just upload one photo per scene plus a button, have the viewer place the photo and look it it, then move on to the next scene (and photo) with the button. I have super high quality photos (around 8.8 MB each) and still they turn out super blurry when scaled up. I am using world tracking, and as it is, if I just place the photos on the plane they appear tiny, so I need to make them bigger but then they become blurry… Is there some sort of way around this? I read other entries and replies that you should just try to upload as high quality photos as possible, but seeing as the highest it will take is 10 MB I am pretty much there. Can I cheat around having to scale the photo up by making the plane smaller somehow, or anything like that? I don’t know, Im confused I feel like what I am trying to do is one of the simplest things but the blurriness just ruins it… Thanks