You DO NOT need permission to use an image if:

The image is in the public domain:Works in the public domain are no longer protected by copyright law and may be used without permission.
The owner has already given permission (open access): Many creators of various images choose to make their work freely available for use through open access licenses. Requirements for these open access licenses can vary, so check the “terms of use” carefully before using an open access work.
Usually determining if images on a website is an open source or grants open access can be found at the bottom of the website’s homepage.
You’ve taken the photo yourself. However, you do have to cite yourself (see Citation for Images: Unpublished Photo Source and In Detail: Using photos of equipment and products).

Example 1: Determining a website as an open source for image use. Our World in Data (https://ourworldindata.org/) is an open and creative commons. As shown in Fig. 7, this information can be found at the bottom of their website. The conditions on what you allowed to use and the terms can be found under the “creative commons” link.

Fig. 7. Example that shows the Our World in Data website as open source via creative commons for images (Our World in Data, 2018).

Example 2: Determining a website as an open source for image use. Similar to the Our World in Data website, Wikimedia Common is also an open source website that allows users to use the images that are not copyrighted. As seen in Fig. 8, the bottom of Wikimedia Commons’ the home page informs you that it is a creative or open commons and under the terms and use allows you to use their images under their terms and conditions.

Fig. 8. Example that shows the website Wikimedia Commons as open source via creative commons for images (Wikimedia Commons, 2018)

When you select a photo that you would like to use from an open source, like Wikimedia Commons, you should see the summary and licensing that informs you of all the information including who the author of the photo is, the year it was taken, the title, and the conditions that allow you to use photo. An example of this can be seen in Fig. 9 (click to view larger image).

Fig. 9. Information and conditions given to users (Wikimedia Commons, 2018).

InDetail: Using photos of equipment and products
For equipment or product used in your research, the generic name should be used, and you should talk about the process or how the equipment or product produces a result or action needed in your research. The use of any equipment or product in your research should solely be forced on its purpose in your study, not the promotion of it. With this in mind, when you are taking the photos of equipment or of a product, their logos should not be the focus. If possible avoid having the logo of the product in the photo. Example: Here is a recognizable piece of equipment, but the logo on the equipment is not clearly seen. In this case, it is important to talk about its function and how it is used in the study, not the brand or the promotion of the brand. Fig. 13. A tractor in a field near Winterbourne Monkton: This tractor pulls a disc harrow in order to break down soil clumps (Marshall, 2008).