When you create content on your site, it is important to highlight it, to support your publication, with images, illustrations, which bring more weight to your subject matter.
Pictures are also a weapon for linking. Naming your image files is to allow Google to understand the meaning of your images.
A good image should reinforce your message. It's up to you to place your images in the right places to make your content enjoyable to read.
First, what is a royalty-free image?
A so-called “royalty-free” image is, by definition, free to be used without having to pay its creators. However, this does not mean that you can do whatever you want with it.
Where can I find royalty-free images?
How can I find royalty-free images for my site, my blog…?
Online services are available. Many of them will ask you to add a photo credit to your publication.
Here are a few of them
Flickr, which allows its members to add photos, with different levels of accessibility, some of which have a Creative Commons license.
Photo-libre, which gathers royalty-free images by category (Business, Nature, Sport,…). The Internet user can make his selection in the category that interests him.
It's up to you!