If necessary they may be placed on a separate page. Those larger than one-half a page should be placed on a separate page. They may also be positioned horizontally when they will not fit on a page vertically. Be sure that the page numbers are in the same position as in other text pages. Photo-reduction of oversized material is allowed in some instances, but this should be approached with caution.
Legibility is the central issue here.
Always refer to your program's approved style guide or to Kate Turabian, A Manual for Writers of Term Papers, Theses, and Dissertations , if your program's guide is silent on the issue . The placement of captions, legends, keys, etc., should also be governed by the program's style manual or by Turabian.