1. What is plagiarism?
The Longman dictionary version 2000 defines “plagiarism” as “the act of using someone else’s words, ideas, or work and pretending they are your own”;”an idea, phrase, story etc, that has been copied from someone else’s work, without stating that this is where it came from.”
From the Merriam-Webster online dictionary, “plagiarism” is considered as below:
: to steal and pass off (the ideas or words of another) as one’s own
: use (another’s production) without crediting the source
: to commit literary theft
: present as new and original an idea or product derived from an existing source
(Source: http://www.merriam-webster.com/dictionary/plagiarize)
According to the explanation applied by Hong Kong Baptist University, plagiarism means “taking someone else’s words or ideas and passing them off as your own” and “is the most common form of intellectual dishonesty.”(Source: http://www.hkbu.edu.hk/~ar/avoiding_plagiarism/)
In my opinion, plagiarism and copies are in the similar way. To be brief, it means that if you use some words or sentences which produced by somebody else, you did not use the quotation marks and state the source neither.
2. Can I legally post any picture on my blog that I have downloaded from the Internet as long as I credit the source?
Well, I think most time we can not do it, but it really depends on the different situation, such as the function of the blog, what the purpose of posting the picture on my blog, where I get the picture from, etc.
Sometimes people posted pictures on their blogs or other places just for fun and sharing, they would of course like you to transship their pictures if you truly did the acknowledgement and for non-profit purpose. On that circumstance it would be fine.
Copyright in photos is a little bit more complicated because the regulation changed several times, we have to handle photo’s copyright depends on the time when it was taken or published, etc. But basically we can say that some famous photos which have been wildly known or used by public, for example, some classic paintings, Iwo Jima flag photo etc, everyone can use them with clear acknowledgement.
Otherwise, I suggest people use photos very carefully unless they are taken by you or you can use them legally.