Answer: In the absence of the Buddha in person, Buddha images are customarily taken to represent his presence, to serve as precious Dharma reminders. They are not meant to be mere decorative images. (Unfortunately, they are commonly abused for commercial purposes today.)
Thus, what we would not do before the Buddha in person, we should not do before his images — such as being uncovered, having sexual activities, sleeping in disarray, pointing our outstretched feet…
Of course, the Buddha in person, being fully enlightened and magnanimous would not mind any of this, even if we are deliberately rude. Yet, being deliberately disrespectful does create negative karma accordingly.
However, if we are not sincere in expression of respect in worldly ways, we are also less likely to be truly respectful in spiritual ways — because we are indeed still very worldly at the moment, even if we imagine otherwise. So are others around us, who might see us as being disrespectful.
Related Article:
Is A Buddha Image In My Bedroom Okay?
https://thedailyenlightenment.com/2012/06/is-a-buddha-image-in-my-bedroom-okay
