Where did you post?
Against popular believe, Lee misses a lot if its not a really obvious pic with a known image hash that gets him notified.
I use a userscript to randomize the hash and he never finds any of my posts on any popular board.
You either have to use a known image, or go to boards where he is like here or /co/ or specific /tv/ threads.
Here on /qa/ you can make a collection of random crops in one pic and he will work on finding every single derpibooru link. But he will still miss a few. And when you call him out on what he misses, in the next post he gets it right.
It also depends a lot on the daytime you post.
Lee is real. He is one person. He sleeps. He has preferred board.
Try it. If you are in the game for some time, you will learn where and when to post to get Lees attention or not.