The above shirts and pants are same size, what I have done is changed the colour combination.
Lets look at the trousers, the black trousers will visually give a slimming effect because lighter colours expand and darker colours contrast. So if you are heavy from lower body like Triangular body shape / Round body shape / Large Rectangular body shape / Large Hourglass body shape shape
Same rule applies to the shirts. If you have a fuller bust or midriff variation opt for dark colour shirts (or blousons preffered)
A darker top / bottom will always reduce the size of that part of your body, its colour perception or as I like to call it Deceptive styling 🙂