This is quite useful.
Since we all (in the steemSTEM community) write education articles, doesn't everything fall under fair use?
About author crediting, is it sufficient to link to the source where the author is named (I mean specific page, not generic homepage), or do we have to name him under the image?
Personally I think it's just courteous to put as much info as you can, but for example in wikicommons it will often say in parentheses that you're free to use it as long as you credit the author, so we should probably adapt accordingly.
Regarding education yes, I've found that legally it's a grey area when it comes to earning from it - whether you're a registered educational facility or whatnot. One of the areas I didn't want to start diving into in this post...