License and attribution of images in compiled work for public outreach I am working on a lager poster about science which will be on display in a museum and may be made available online. I intend to compile it using images from different sources. Some are own work, some are Wikimedia Common (Public domain or Creative Commons), others may be plots/graphics from (mostly historic) journal articles (they are usually not open access). 

To my understanding, the use of these sources for non-profit/academic purposes is free if attributed correctly. However, I am unsure about the consequences of compiling or slightly modifying these works. Journals may have their own license policies but my understanding is that reuse for such purposes is generally accepted. In addition plots which represent measured data may not be protected, it seems.

Here are some of my concerns:

Using a Creative Commons image may require me to publish the whole work under the same Creative Commons license. I suppose that this is not ok with licenses/copyright policies that apply for plots or graphics from journal articles?

The different images should fit in the design of the whole. In order to achieve this I may need to make minor changes, like cropping the image or changing the background color. Will such modifications be ok with Public Domain licensed images and the ones from journals?

May the license of the whole work be determined by the fact that I am working for a public university (even though this sort of work is probably not described in my work contract, so it could be interpreted as work which I do in my spare time)?  

Generally, are there some good online resources which explain the license issues and attribution of images for this kind of work?

Here are some links I know:

http://creativecommons.org.au/learn/fact-sheets/attribution/

https://commons.wikimedia.org/wiki/Commons:Credit_line

http://fairuse.stanford.edu/overview/
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!