4500 x 5400 pixels is 15 x 18 inches at 300 DPI, and it is the working canvas most direct-to-garment print areas are built around. It is worth being precise about its status: Printful and Printify do not publish 4500 x 5400 as a platform requirement. Printify states a recommended 300 DPI and puts the actual pixel dimensions inside Product Creator, per product and per print provider. Printful asks for 150 DPI on most apparel, 300 DPI on paper and stickers, and sizes tied to each product's print area. So 4500 x 5400 is a sensible master canvas that covers a standard adult front print — not a universal spec you can trust for every product. The practical rule: build the master at 4500 x 5400, then export per product at the dimensions that product's File guidelines actually list. And resize down, never up: enlarging a 2000 px design to 4500 px adds pixels and no detail, which is exactly what Printful means when it says not to copy a design into a template and scale it up. Skwish resizes to exact pixel dimensions with the aspect ratio preserved or forced, and compresses in the same pass.