Not all images you find on the Internet are free to use. Some have licenses that tell you what you can and cannot do with the images. It is not legal to reuse licensed images without the creators permission, however, in some cases, you may reuse or modify an image if you provide attribution to the creator.
Source: Visme, Published May 23, 2019
If you are using Google to find images, use the limiter found under Tools, Usage Rights to filter results to images with a Creative Commons license.
