As people visualize and imagine things differently I don't think its a good idea to have an image there other than the kanji (if its your own personal notes then its fine). I know what you are saying but that's for each person to think of and visualize for themselves. Each person is different and may have a completely different image for the same kanji. Like above example, for me I picture the hilt of a sword and its handle (no blade) with the place for the hand to grip round 刀 rather than a broadsword like you have.
Also tests are a great thing as they make/force the brain try to remember/recall something you've already learnt and it then tends to stay memorised for much longer before you need to refamiliarise yourself with it again. You learn from your mistakes, so if you get things wrong in a test, they tend to stay in the memory longer and you know which areas need work on.