Artists and sometimes even experienced professionals such as Designers will use photos that they find in the Internet to use for their next painting or drawing or designs. If you do this, very often you'll be breaking copyright law and infringing on someone else's intellectual property.
You need to use photos that have a special license attached to them. The special licenses we want to look for are:
1) Creative Commons Zero License (CC0)
2) Attribution Licence
With both of these licenses, you can make any kind of artwork you like from the photo without asking permission. You can sell your artwork or make prints of your artwork and sell those, or otherwise use your artwork in any commercial design. The only difference is that the CC0 License doesn't require your credit to the owner of the photograph whereas the Attribution License does.
Some of the sites I've listed below contain mostly CC0 images.The sites below are listed in the order of my own personal preference.
Ready? Let's find you some inspiring free photos that you can use for your next masterpiece!
1) Pixabay https://pixabay.com
This is my personal favorite website. I use this website for a vast majority of my references.
Pixabay is a vibrant community of creatives, sharing copyright free images and videos. All of the content in this website are under Creative Commons Zero License (CC0). A CC0 license means you are free to use any image on the site, even if you want to go on to sell your artwork in any commercial form. The site is very easy to browse and you can quickly check for the CC0 license next to the image.
2) Unsplash https://unsplash.com
If you are looking for stunning photographs from professional photographers then this is the place for you. All the Images are under a CC0 license so you can browse with more confidence. The only downside is the Category page is bit limited and it is hard to spot at the first glance. Having said that their search tool is great and this site is best used for inspiration rather than looking out for a very specific subject.
3) Pexels https://www.pexels.com
This site offers a huge collection of high-quality free stock photos from other sites around the web. Very easy to browse lots of images quickly and all are mostly published in the CC0 license. In this site the images are nicely laid out for fast browsing. The only downside is that they don't have a huge collection as Pixabay.
4) Public Domain Pictures https://www.publicdomainpictures.net/en/
This site offers over 324,878 photographs published under Creative Commons Zero, with many of a very high quality. Each image has a Premium and Free download option. The Premium option allows you to download a higher resolution version but the free option is good enough for most artists purposes.
5) Wikimedia Commons https://commons.wikimedia.org/wiki/Main_Page
Wikimedia is a part of the Wikipedia family. It contains over 30million digital files that editors of Wikipedia can use, or that can be downloaded by anyone for other uses. But you need to be careful even though it is on Wikimedia. It offers the largest collection of free images online. If you are looking for something specific then you will probably find it here. Many images ( but not all) are published under the CC0 license or declared as public domain. Make sure you check. Some disadvantages using this site is you have to rely on their search box and you cannot browse by category. Not all images are in the public domain. Make sure to check the license under each image.
Please Note: In this list, I have not used Wikimedia Commons that much mainly because of all these disadvantages that I have listed above.
Let me know in the comments below if you found this useful and if you know of any other websites that I can add to my list. Thank you for reading!