Capsule imaging trick:
It's very simple! When I buy something, I save a picture of it. I put it into a PPT. I do a "format picture" --> "remove background" on it. Then it's like playing with paper dolls, like when I was a kid.
I can organize the pictures by color, by capsule, etc. Or just play around and see what accessories or shoes or other pieces might pull it all together. When I have to pack for a trip, I visualize it all in my PPT first, before doing a try on and packing final selections. I can play in my closet without leaving my laptop.
Tips:
Not every item can have the background removed successfully. Cropping close as possible works for these. Also I prefer images of clothes without models wearing them, so I frequently do an image search with the word "polyvore" because you can find items without models wearing them, they might not be the exact item, but close enough! If you want to catalog items that you bought long ago, just google terms and you can get an approximation.
And YES to dresses, and YES finding the right underwear is key. I have lamented forever that underwear does not come in petite sizes, and by petite I don't mean slim. I mean scaled to a shorter vertical height. It's not impossible, but no not easy either. Once I find underwear that works, I duplicate the hell out of it.