I don’t know if this counts as a theological difference, but the East and the West really have a quite different understanding of the function of sacred images. The East considers icons to be not simply artworks, but ‘windows into Heaven’, making present the saint depicted in a supernatural, almost sacramental way. In the West, however, we historically paid more focus on the practical functions of images: their decorative, teaching, and commemorative functions. We also venerate images, but our understanding of the mechanics behind them work quite differently from the East.
We don’t so much say that the saints are ‘present’ via their images and share in their holy essence and miracle-working power; for us Westerns, it’s more like images are reminders that help the worshiper concentrate and call to mind the subject portrayed, hence the common line used by (Latin) apologists comparing sacred images to photographs. (You might say that the Protestant view of images is the Western one taken to radical extremes.) I suspect that from an Eastern POV, the icon isn’t so much like a photograph or a commemorative monument, to which Latin apologists usually compare images to, but more like a shop window that allows you to see ‘the other side’.
That’s really the reason why Eastern iconography have a strictly-defined canon the iconographer must subscribe to and have layers of symbolism attached to even the smallest detail, while Western iconography is much looser in how sacred subjects should be portrayed and has a generally more literalistic, down-to-earth approach. From a Western POV, as long as the image can remind you of and fix your mind on Jesus, it doesn’t really matter what way you portray Him.