For a reference, I am a size 4 in American Eagle jeans, about a size 26-28 depending on the day. I always buy small leggings and medium shorts for extra room.
I bought these really not knowing if I would like them or not. Upon receiving them, they didn't look like I would love them. I washed them in cold water inside out and dried them. They are not see through at all!!!! However, you may be able to see underwear lines and possibly cellulite because they are pretty thin. They're kind of a brushed material, but super athletic feel to them. The model has the bottom of the legging around her feet, so they are pretty long. They have a weird scrunch at the bottom that is so functional because if you have short legs, they look like they are supposed to be scrunched, but if you have long legs, they fit PERFECT. I have long legs and they aren't too short (finally). They have a two seam crotch gusset that runs from one knee to the other, so you won't get camel toe. Definitely recommend. I have both colors and wish they made more!!