Question: How do you pray to Jesus without seeing an image of Him?
Response: I never see an image of Jesus when I pray. From my background as a Roman Catholic and one having a degree in fine arts, I've seen a lot of images of Jesus that men have painted, drawn, or sculpted—but none were true images. They were depictions of what artists have in their minds regarding what they think Jesus looked like. No matter how impressive any image may have been, it was nevertheless a false image.
I've been told by some Christians that having an image of Jesus in their mind helps them with their prayer life. It may seem to help, and I'm sure they are sincere, but their practice is neither practical nor biblical.
It's impractical because the person is not praying to Jesus but rather to a false image of Him. It would be like having an artist draw a picture of someone I have phone conversations with—someone neither the artist nor I have ever seen. Yet I declare that when I stare at the picture during my phone conversations, it makes me feel good about the person to whom I'm talking. That's not only a delusion, it's idolatry.
Conjuring up an image of Jesus in my mind—that is, a depiction of what He looked like, although I've never seen Him—is a form of idolatry. It is idolatry because Jesus Christ, the God Man, is being fashioned according to the mind of a fallen, finite human being. The result, no matter how helpful it may seem, would be both demeaning and degrading in comparison to the true, godly image of Christ
For those who, when they pray, are bothered by man's images of Jesus (seen in movies, paintings, statues, icons, etc.), I recommend meditating on verses that so glorify Jesus that one's fleshly imagination will be put to shame and be delivered from such a distraction. For example: "[Jesus] is the image of the invisible God, the firstborn of every creature: For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: And he is before all things, and by him all things consist. And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence. For it pleased the Father that in him should all fulness dwell" (Colossians:1:15-19). Any image of Jesus that falls short of those characteristics (which they all do to the extreme!) is "another Jesus," a "false Christ," of which Jesus declared there would be many in the last days.