EDIT.
Deleted some lines here as I managed to work out the what I had in mind in a mere couple of minutes.
Of course another issue still stands: where did all the GIFs come from during my research? The problem is I cannot convert them (the PNGs are far less, thankfully) to the same number (001, 002, etc.) is it sometimes taken by a JPG that occupied an inline shape further up within the document. Anyway, I'll try to work it out outside of Word.

Cheers again

Z.