[markom]

If pictures are not that important to you, you can first quickly crop pdf using Briss app (separating columns cutting through pictures) and then use k2pdfopt.

Here I've left a few letters of the adjoining column partly visible too, but you can easily draw a cropping rectangles closer to the text of each column.

Maybe Willus can find a way to do this page cropping automatically throughout pdf, depending on the number of columns in the current page.