DPI doesn't exist in AE. The concept of DPI is irrelevant in AE. AE deals only in dimensions determined by the number of horizontal and vertical pixels. It cares NOTHING about how closely pixels are jammed together.
A 6-inch-wide image at 100 DPI is 600 pixels wide in AE.
A 1-inch-wide image at 600 DPI is 600 pixels wide in AE.
Do you see a difference? No. Not if you're AE.