Information is a pretty broad concept and not one I've had reason to research much (though now I'm aware of the gap in my knowledge, maybe that will change!), but as for pictures:
There is indeed a legal way to go about using pictures on a blog. That you realize that and are even asking puts you steps ahead of most first-time bloggers, who simply don't realize that Google image search isn't a free-for-all.
I'm sure you've already heard the "It's best to use your own original pictures" speech, which is certainly true as you can then share the photos on media sites such as Pinterest and hope to attract attention. Plus no copyright issues to worry about. But you don't always have pictures for something you want to write about, of course.
There are a lot of websites that offer legal-to-use, free photos or images (such as drawings and clipart). Some don't require any sort of credit. Most will stipulate that you need to credit the source, and often provide a link, in the photo's caption or somewhere on the page. I find the following websites the most helpful for providing relevant content and making their rules very clear on the front page and individual pages:
Flickr: Creative Commons: https://www.flickr.com/creativecommons/
Oh, and of course you absolutely can always politely contact the owner of a photo and ask if you might use the picture so long as you give credit back to them. The worst they can do is say no.