Help! Trying to order some cheap summer H&M dresses for my soon to be 6 year old. She's on the short side of average (maybe 44 inches), skinny (35 lbs), and very leggy.

I've got 4-6's from last year that still fit, but look a little on the short side. However, I feel like she'll be swimming in a 6-8. Our closest H&M is NOT close.....does anybody happen to have a 4-6 and 6-8 basic tank dresses on hand they could photograph laid on top of each other to show me the difference! I'd appreciate it so much!