Is he bored?

I send my man sexy pictures throughout the day sometimes and he seems bored with them. Half the time he doesn't even respond after he opens them. I'm considering just not sending them all together. His nonresponsiveness is not helping my self esteem issues. Maybe I'm just being needy. Idfk. 
Note I never send my face in them and he has a 5 second viewing window on snapchat. 
The pictures usually have some caption about what I'd like to do to him, when he will be here, etc. or nothing at all in some cases. The range in all angles, some in lingerie, some totally nude. Sometimes others are like a strip tease.