A few years ago, the pictures on the websites that offered free pictures were both bad and often in small sizes. In recent years, that has changed dramatically and some of these free photo archives have pictures shot by professional photographers who make them available to anyone without asking for anything in return.
Most offer the images are under the license Creative Common CC0 while some of the sites have prepared their own version of this license, where they e.g. may ask you to credit the photographer if you use an image or it restricts the use of the image to some extent.
It is your responsibility to ensure that you are legally allowed to use the images you find - and it can be extremely difficult to assess this if you, for example search via google - therefore it can be an advantage to use the many image archives because they try to ensure that the images are legal.
I have compiled a list of good quality archives - a total of 20 different ones that can offer a bit of everything. The order is random.
Unsplash has managed to attract some of the best professional and amateur photographers, and in my opinion has a quality level that is very high. Unfortunately, their search function is not particularly good and it may take time to find the images that will work best for you. All images are published under their own license, which is very similar to CC0 - you may not add the images to other image archives.
See my photos on Unsplash here @jenspeter
Last day of March in 2021 they informed that they have been bought by Getty Images.
StockSnap.io is a good and large collection with very up-to-date images. Their search function is limited to searching by keywords and searching by categories. All images are released under the CC0 license.
Beautiful pictures and a really good collection of pictures - a little smaller than many others, but in a good quality. They also have videos. Everything is published under CC0.
Burst image archive is made by the people behind Shopify. A good collection and good pictures - they have two license types, CC0 and their own. For both types, you can use the images in your own projects without restrictions - however, you must not add the images to other similar image archives.
Foodiesfeed are images of food ... high resolution and beautiful images of everything related to food. Definitely relevant for anyone with a cafe or eatery - if you look a little you can find really good pictures. All images are CC0.
Slightly more humorous photos - at least many of the photos were taken with a different approach to photography. All photos are free and by Ryan McGuire, an American artist. A significantly smaller selection, but if you find the right picture here, there is a good chance that not so many have seen it elsewhere.
Negative Space has many great pictures and is actively outreach to find great photographers who can share their pictures through their site. There are many pictures on the site but fewer than the first ones I mentioned. All images are published under CC0.
Nice collection - also by amateurs, which allows you to find pictures that could have been taken by yourself. Sometimes it can seem more authentic. All images are published under the CC0 license.
Slightly more ordinary pictures but a nice selection and all in good quality. All photos are shot by Jeffery Betts and are released under CC0.
Again nice pictures in good resolution. At first glance, it seems like many of the pictures were taken by good amateurs, but I can not be sure. All images are published under CC0.
One of the first to post pictures for free (the name says something about their attitude). I still find DTS extremely interesting. You can only access the pictures by subscribing to them - they send approx. once a month a handful of pictures that you can download and use as you like. In recent years, the project has become more and more artistic. All images are released under their own license, which limits the use a bit, but you can use them almost as freely as all the others.
Large collection and opportunity to buy access to even more. Excellent quality by many different photographers. All are published under CC0.
The archive of old pictures - many in black and white. The images are usually released and can be used as you wish, but there are exceptions. You must check the right yourself by following the link to the original release, which is always with the image. All photos are from Flickr.
German site that has grown big. Their reputation has sometimes been a bit bad because they do not check the rights to the images they receive particularly thoroughly ('borrowed' from other sites) and some less good images also slip through their control. Despite that, there are a lot of pictures on Pixabay. Even I have a collection there. All are published under CC0.
Good pictures in high quality and a nice selection. Site and photos are all by Karolina. She has a particularly good feature where you can search images by color. Her pictures can be used as you wish with a few restrictions (eg do not sell them).
A site by Jay Mantri who also took all the pictures. A slightly smaller number but definitely interesting good pictures that can be used as you wish (CC0).
Here, too, it is a single person behind all the images released under the free license CC0.
Hope the list has given you a few ideas to find great images that match your style. You are very welcome to share other image archives that you think are missing or interesting.