Struggling to find images for graphic tee, models wearing printed t-shirts

I do not know what graphic tee is, but the solid T-shirts are mostly because too much design may cause legal problems because of copyright issues. I, as a contributor, can contribute only elements that are my design or where I have a property release from the design's owner. It's a complicated issue. At the end, I fear that you either need to take your photos (depending on the work you're doing, your constraints to IP issues are less), or you need to photoshop the T-shirts with your design.