This is a great post about a topic that we often don't discuss too much here on Steemit. I really think there are many popular bloggers here who need to improve their use of crediting images, and as you said, it's not really hard once you know how to do it.

I have always taken the extra time to properly find and credit images that are legal to use on my blog, and not only is this a guarantee that I won't get in legal trouble, it also feels great to know that I am using photos from people who wants their photos to be spread, shared and enjoyed, instead of stealing images from someone who do not want this.

I find most of my photos from Wikimedia Commons, which is a great resource for CC images. All photos there can be used for commercial use (which Steemit blog posts by default is unless you decline payout), as long as you give proper credit. Their search function is far from the best, but it is just fine when I mostly want photos of different species of animals.