Long Term Image-Topic Recovery

I’m new to using memory techniques. So far I’ve built a quick system to play with memorizing a deck of cards, which worked well for recovering the order within a few hours or weeks. After a few months, though, the images I built weren’t obviously linked to my system. Not being tied to the order of cards, I figured maybe the content had something to do with the recovery?

I then wrote down a list of rooms in my house and linked the rooms to chapters of a math course I’m taking. I’d like to remember the techniques for solving problems for a long time, right?! So for a chapter title like “Reduction of Order”, I imagine anthropomorphic ant-people walking around the room and destroying the place: reducing the order in the room. This chaotic scene is easy to remember, but a month or so goes by and I’m left wondering how the destruction of this room relates to to my math course.

I guess the image is good, but the link is bad. Anyone else have this issue or know of keywords to search up?