In your research report, if you include images that you find through Google search, on a website, in a book, or in a journal/magazine paper, be sure to cite it properly. By citing the image, you avoid plagiarism and give credit to the creator of the image. At a minimum, image citation should include the following elements:
Title of image
Creator, artist, or photographer
Source of the image (website, book, paper, database, poster, etc)
If you are writing an academic paper and use an image to support an idea or argument then you would cite that image according to a specific citation style, e.g. AIP, APA, or MLA.
When to Provide Attribution:
Attribution is to acknowledge the creator(s) who hold the copyright of an image. You may attribute an image used for presentation, web page, or other formats that do not require a specific citation style. For example, if you use an image to enhance a web page or a presentation, you need to attribute the image to its creator.
If you use the image above to support the argument that the two satellites of Mars are potato-shaped in your research paper, you would need to cite it using a specific citation style.
If you use this image only to make your website more visually appealing, you would need to provide attribution. You do not need to follow a specific citation style as long as the key elements (title, creator, source) are included.