I don't think so. My original files say they are 51.3 MB, 5184 px x 3456 px 300 px/in - I feel like they've grown somehow. I've just looked at a few after flattening, before cropping, and they're all that big. Holy moly, I just looked at one that wasn't even that complex of an edit and the .psd says it's 101.53 MB. Not something I've been paying much attention to until now, but that doesn't seem right.
Edit - this is my stupid moment - I saved the flattened, cropped ones as .psd instead of a .jpg. I'll bet that's it? Derp!!!