Unless I'm missing something, when you paste as a picture, Office locks the elements into place relative to each other, so that all sizing is proportional. In practice, it is typically the case that when working in Excel, sizes appear reasonable, as if they should easily transfer to a standard page, but they actually require considerable shrinking to do so. For instance, what seems to be a reasonable number of columns in Excel turns out to need 13 or 15 inches when printed, not the 7 or 7.5 of a portrait-oriented standard page, or even 9 or 9.5 if turned to landscape.

I suspect this may be your problem in going between the two. It may help you to turn on Excel's page boundary view (View/Page Break View).

Best,
Ulodesk