Resolution for 8×10 photos?

Last year, I found $3 calendars for the artists I wanted to use.  This coming year I wanted to do Renior, Seurat, and VanGogh.  I have a VanGogh calendar, and could get a Renior one fairly easily but still need Seurat prints for display and then smaller copies for dd’s book.  I have been printing 4×6 photos for the book easily at our local pharmacy but I want to print something larger for our display prints.  If I use a file from abcgallery.com or artrenewal.com are they large enough to print decently at 8×10?  I will probably have to order them from an online walgreens, walmart, target, ect. so I don’t want to do them if they won’t look nice but I don’t want to do just one test print because of shipping charges.

I had heard about making a print your screensaver for the week, but we have a laptop and I try to keep it closed except for afternoon rest time so that won’t work.  I can also get a book from the library, but how would I keep that on display all week?

Do any of you know anything about printing resolution or have any alternatives for displaying the prints each week?

Thanks 🙂