I'd like to have a bit of a rant.  A photo of one of my designs ended up on a very popular blog that I read regularly.  She is a professional blogger and has a large following.  This blogger used my image and didn't even bother to give me credit.  Nothing.  Luckily, in this post-Pinterest internet world I have been watermarking everything.  So the image at least had that, if someone really wanted to type my name into google they could and would find me.  But this is an issue that has been bothering me since I entered the blog world.  Everyone deserves proper credit.  But what is proper credit?

I was happy looking at the comments of this particular post, that someone else had voiced their dissatisfaction that the sources were not present.  Thank you Giulia!

So let me tell you what is not proper credit: 1. unknown - um, don't use the image or track down the original source.  Stop spreading this around. 2. img via Pinterest - Pinterest (or tumblr, or the like) is not a source, track down original source. 3. via - a little more description would be nice 4. via A Curated Lifestyle (or any blog) - unless the blog is the original and direct source, this is not proper credit

If everyone would do a little more due diligence in crediting then it would be less trouble to actually find the original source.  So what is proper credit?

A direct link (to the image if possible) to the original source of the photo.  
You want to make this super-easy for people if they like what they see to track it down.  Even if you are only a blog reader, stand up and let bloggers know that everyone deserves credit and you want original sources.
I do my absolute best on this blog to always credit sources - often times spending up to a hour tracking down the original source.  Its not easy - a lot of use of google image search and clicking through blogs and reading to see if the source is to be found.  This includes images that I use in a larger context or design board.  If I can do it, everyone should do it.  So let's just do it.  Do it.
PS - I sent Giulia a note thanking her for speaking up and she wrote a similar post she shared with me.
UPDATE: This was originally written in 2012, today in July 2015 I have a different view of this topic.  There are some companies and photographers who have been avid in the past few years in pursuing copyright infringement.  If you use photos on your site, you must have a license for those photos, either by purchasing a license, by taking the photos yourself, or a creative commons license.  Anything else is opening yourself up to potential headaches and possible litigation.  I have erased hundreds of photos and blog posts from my website  in response to this potential danger.  Sometimes crediting a source isn't enough.