In this talk I show how to improve difference imaging analysis (DIA) of lensed quasars over long periods of time using Gaia proper motions. DIA requires the subtraction of a suitably convolved reference image from the individual images of a monitoring campaign, using stars in the field to align the images. I demonstrate how to use Gaia DR3 proper motions to enable a correct alignment and apply the method to the light curves of the three gravitationally lensed quasars HE1104-1805, HE2149-2745 and Q2237+0305, obtained from the ARI quasar monitoring program at the Las Cumbres Observatory (LCO) from 2014 to 2022. The light curves of individual quasar images display intrinsic quasar variations and are affected by time delays and chromatic microlensing.