Legal exceptions are generally used as a fall-back when something is not covered by, or permitted under, the University's various copyright licences (see the Books and Journals and Other Resources sections of this LibGuide).
Sections 32 to 36 of the Copyright, Designs and Patents Act 1988 cover education exceptions. Generally speaking, if there's something you want to use that you normally wouldn't be able to because of copyright restrictions, you can use it if you adhere to the conditions as set out in the Act.
More specifically, Section 32 states that, for the purposes of 'illustration for instruction', you can copy anything provided that:
The above does not include re-using a copyrighted work (especially an image) to make something look nice - it must have instructional value.
*Generally speaking, where the re-use would not adversely affect sales of the work, and the amount being copied is reasonable and appropriate to the context in which it is being used, it is likely to be considered fair. 5% of a work is widely acknowledged to reflect the spirit of fair dealing. Images, maps and diagrams present particular problems, but re-use of a low resolution copy could be considered fair, if deemed appropriate to the context in which the item is used.