License and attribution of images in compiled work for public outreach
There's a lot of confusion around this sort of thing in academic circles, because academics have been trained heavily about attribution, but attribution is mostly orthogonal to copyright. There is no general right to use things for academic/non-profit purposes, unless copyright law in your country happens to include "fair use" or similar provisions. They vary from country to country so I can't advise on them. 

Some specifics, based on what you asked:


Something in the public domain can be used however you like, as the author has relinquished all copyright claims and "gifted" the work to the public.  Thus you can use it, modify it, etc. However, do not assume (as some do) that anything you see online is public domain. It's probably best to assume that something isn't unless you see a statement to that effect.
Something with a creative commons licence can be used according to the terms of that licence. The various varieties are quite self-explanatory. All will allow you to reuse the work for non-commercial purposes, but not all allow you to modify it (the "no derivatives" variants). 
Something without any stated licence or that expressly reserves rights should not be used without permission - except possibly as provided for by any "fair use" style provisions that your country may have. 


Generally the licence for your work need not be controlled by the works that it contains - "viral" or "copyleft" terms such as those of the GPL are not common outside of software licencing. However, if you choose a licence more permissive than that of works that your document contains, you should make it clear that it does not apply to (eg) those figures. 

Disclaimer: I am not a lawyer, and this is not legal advice; any of the above may be wrong in your, or any other, jurisdiction!