Yup. It’s finding what flows and fits for you. We can give examples, but only you will know what works best.
Practice can help you find your strengths, and then you can leverage them to success. It’s like athletics: some activities you will excel at more easily than others, but there’s almost nothing you can’t do reasonably well with some practice.
I try to keep in mind a few basic principles for images (this is my own list, there are others more extensive and detailed) :
Vivid - the image has clear, even luminous, colours, and is sharp where it needs to be. If you’ve ever gone into a place selling TVs and see the demo pictures, the imagery they use is designed to pop, catch your attention, draw you in, and impress you with the pretty pictures. That’s kind of thing. Colours that create good contrast can stand out, but you don’t want too many together. The white-painted face of the red-armed, black cloak wearing woman is clear enough without being confusing. I wouldn’t add magenta shoes with green and pink striped laces unless I already had a very clear image of those shoes elsewhere in my memory, or they’ll end up just one colour with little meaning. Clarity is often more important than detail in one image - you can always use additional images.
Interactive - action in the image itself, or that relates the image scene to its surroundings. A trick I picked up is to ask why the action occurs, which better relates the action to the image. If Jack Bauer is dancing on the table, why? Is he drunk, is he happy, or is he being a distraction? How does that relate to me or something else here? It creates more context for the image, which adds more connections in your memory.
Emotive - emotional content. Does this evoke an emotional response in me? Is there an emotional response I can relate to happening here? If the person in your image and you have related emotional states, that’s useful, too. Any strong reaction is usable, but positive seems to work better than negative for most people - that said, disgust can be strong enough sometimes to work; I think because we like to think of things that are positive, but we need to actively avoid things that disgust us, whilst things we dislike or find mildly disturbing we tend to not think about so much. But, you see what works for you!
Weird - anything weird or bizarre. Things that are too far out can get garbled, but a tiny elephant with a big blue bow tie can be strange enough without being insanely odd. That said, mythical creatures can be memorable (cyclops, pegasus, dragon, medusa, Griffin, giant) so if a three-headed court judge is what works, try going with it.
Sensory - using your senses, because each is another connection that might make it more memorable. As well as the usual five, you can include things like your sense of balance, or your aesthetic sense. If you have three items together, is it more memorable in a horizontal or vertical line, or staggered like steps, or in a triangle? Is the pleasingness of symmetry more memorable, or does asymmetry make it more detailed and interesting?
Vivid - Interactive - Emotive - Weird - Sensory.
On top of that, it needs to be easy to see any one image at once. A mouse in a top hat is easy. An elephant with a different object on each leg is much harder.
Another tip is to have preset images for some things you’ll use a lot. Every telephone number I’ve used begins with a zero, so instead of encoding that zero with any other number, I put a yellow telephone at the start, which tells me it’s a phone number. I’ve used Wednesday Addams for answers to “when” questions - a fun image to use, because of her attitude and actions in strange situations! Images for months can save you a step in reading back a date, because one part of it automatically tells you there’s a month involved, and therefore a date. You can come up with any other similarly useful lists, but the important thing is to have these images as solid, fixed purpose images, so don’t use things you’ll need to use elsewhere.
(There’s incredibly few occasions I’ll need an old dial banana-yellow telephone, or to incorporate Wednesday Addams, in things I intend to memorise other than the purposes I’ve stated. Although those two are clear in my mind, I’m going to build a little imaginary amphitheatre and put them in thematic groups, for ease of checking & reviewing what they mean - so Wednesday will be in a group with Wyatt Earp, a specific Dr Watson, and a specific witch (“which”), while the yellow telephone, a bright blue bird, and a red outlined envelope will be another group.)
That’s all I can think of for now!