Creators of images have rights, such as the right to say how their image can be used. That means that you need to look carefully at the permissions the creator has granted. Make sure you are not violating the permitted use given by the creator.
The following websites provide collections of images you might be able to use. In many cases, the creator's permissions are next to the image.
2. What information do I need to provide near the image (or at the bottom of the page)?
"A good rule of thumb is to use the acronym TASL, which stands for Title, Author, Source, License.
Title - What is the name of the material?
If a title was provided for the material, include it. Sometimes a title is not provided; in that case, don't worry about it.
Author - Who owns the material?
Name the author or authors of the material in question. Sometimes, the licensor may want you to give credit to some other entity, like a company or pseudonym. In rare cases, the licensor may not want to be attributed at all. In all of these cases, just do what they request.
Source - Where can I find it?
Since you somehow accessed the material, you know where to find it. Provide the source of the material so others can, too. Since we live in the age of the Internet, this is usually a URL or hyperlink where the material resides.
License - How can I use it?
You are obviously using the material for free thanks to the CC license, so make note of it. Don't just say the material is Creative Commons, because that says nothing about how the material can actually be used. Remember that there are six different CC licenses; which one is the material under? Name and provide a link to it, eg. http://creativecommons.org/licenses/by/4.0/ for CC BY.
→ If the licensor included a license notice with more information, include that as well."
"Best Practices for Attribution" from the Creative Commons Wiki shared under a Creative Commons Attribution License 4.0.