Even if you do not think of yourself as a "visual learner," we humans tend to think in pictures.
Because of this, (just about) every company creates a mascot or logo to represent their company and/or a good or service they offer.
The more you see a picture of a mascot, logo, etc., the more familiar you subconsciously become with the company they represent.
Companies do not do this to exercise your ability of image association, but to make money.
The more familiar you become with a company and their overall brand, the more likely you are to purchase a good or service they offer.
Thus logos, mascots and images in general have a very powerful associative effect on the mind. Everybody knows this; both the companies designing them and the people consuming them.
If it is acceptable to use mascots to link a sometimes abstract corporate identity with a tangible image for the sole purpose of making money, could not this same principle be used to make abstract information more tangible and appealing for the sole purpose of learning?
I personally think so. For the last couple of weeks I have been experimenting with using various images to make subjects more "sticky," and it's working.
As an exercise I have created "mascots" for countries, scientific principles, elements of the periodic table, major and minor wars, large-scale natural disasters, and different translations of various books. While some of these exercises have been fruitless, the great majority of applications are yielding positive results. Having an image associated with something abstract makes it easy to differentiate that information from a similar concept, person, etc.
I am still experimenting with assigning mascots to stuff, and I have a feeling this will be ongoing. Just know that it is working and its application is much more broad than I initially thought.
To conclude, mascots are useful in linking abstract things to tangible things. Spaced repetition software makes forming and maintaining this link very easy. So, the next time you have trouble keeping two similarly related ideas separate, assign two cool-looking characters to represent those ideas, and use Supermemo (Or whatever SRS you use) to make sure those two characters are never confused.
I've found the "pixiv" Japanese artist community and conceptart.org to be an almost bottomless pit of original artwork and characters. "Pixiv" seems to be a Japanese version of Deviantart. While there are many original characters to work with, you have to deal with and skip over the anime tropes that are too wahjah for your tastes.