Word doesn't allow you to change the thickness of the column separator

If you insert the image as a wrapped image, it can span multiple columns - as can a textbox or a wrapped table. Otherwise, you'd need to insert continuous Section breaks either side of where the object is to go and format the intervening section for a single column. If you do that, though, your text won't continue across either of the Section breaks.

PS: Please stop posting new questions in the same thread. Start a new thread for a new question.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]