Being from Germany and the concept of fair-use not being something that is used there at all, I always properly attribute images I use in answers with the source and the author.
Example: How is human waste taken care of on commercial aircraft?

Since most of the images on Wikimedia Commons or other sources are published under Creative Commons licenses, I happily provide the requested attribution below the image, abusing the available HTML markup in StackExchange to provide a non-intrusive attribution line:

<br><sup>(Image Source: <<Name of Source with Link>> - Author: <<Name of Author>>)</sup>


producing below the image:

(Image Source: http://avation.stackexchange.com - Author: SentryRaven)

In a recent discussion with another member of StackExchange, we discussed if fair use can be used on virtually any document or image on the internet, since SE and IMGUR are hosted in the US. The question whether this is the case or not should probably be asked in a separate question, but as far as I understand, under fair-use an attribution of source or author it not required.

My question however is:
To form a best practice or good standard, should we try to attribute images properly and should we encourage other users to do the same in comments or attribute images/replace images where we can identify the source quickly?

• if I am required to provide attribution for every photo I post, I will stop posting photos
– rbp
Feb 27 '15 at 16:44
• @rbp it can just be a link to the wikimedia page (that's what I do) Feb 27 '15 at 16:46
• and I say: go for it! if its something that belongs on every wiki photo, then it should be added to the software, not as a rule
– rbp
Feb 27 '15 at 16:51
• @ratchetfreak One note of caution about linking to Wikimedia Commons - I would make sure you post the image to the Stack Exchange imgur & use that in the post (you can make the clicky-link go back to Wikimedia or note the source in text if you want). Occasionally the Wikimedia Commons people go on a religious purge of stuff they think is "out of scope", and lots of links get broken. Mar 3 '15 at 21:45

The short answer appears to be yes.

As you might expect, this has been discussed already on meta.SE, where the conclusions are:

• Having content of all kinds (including pictures) directly available in the question/answer is very useful
• When you use content from another site you need to follow the licensing terms of that site. For example, if you use content from SE then proper attribution is required by the SE licensing conditions
• It's polite, whatever the official and/or legal requirements might be

And notice that you cannot expect moderators to take care of this.

• Re: the SE licensing conditions, note that those apply to content from Stack Exchange sites being used elsewhere. Content from other sites being used here is subject to whatever licensing terms that site uses, and/or "fair use" laws in various jurisdictions & need to be attributed according to their licenses. Everything else you said still holds though :) Mar 3 '15 at 21:25
• @voretaq7 You see, this is why I usually avoid legal questions, it's too easy to miss the fine print :-) I'll update my answer to include that Mar 3 '15 at 21:26

Generally we should try to attribute images "appropriately" (as required by their license), and only use images we have a genuine belief are available for use (public domain, Creative Commons or similarly permissive licenses, or used according to appropriate "fair use" laws).

(There's a bit of actual policy on this in sections 3 & 15 of the Stack Exchange terms of service - which nobody ever reads, but everybody SHOULD.)

The standards of attribution on Stack Exchange sites tend to have substantially less rigor than in academic papers. For example, if you crib an image from the Airplane Flying Handbook (an FAA/Government publication, and so broadly "available for educational use") I don't think it's necessary to include a link to the PDF and cite the chapter/page you found it on unless someone asks about it (and attributing it in a comment is often "Good Enough" if someone asks, at least in my not-a-lawyer opinion).

Similarly if you crib images to include in your answer and then link to the original source as a reference somewhere (or mention the original source as something easy to track down - like "the POH checklist" or "The FAA's Airplane Flying Handbook" I think that is sometimes adequate attribution (similar to how it is when quoting text), and it's often less intrusive than specifically noting "I got this picture from blah" and breaking up the flow of the answer.