A black and white photo of a propeller plane. Plane aircraft war plane.

People keep searching online for one question: "Where can I find free high-resolution stock images that are cleared to use without any copyright restrictions? Where to find images for blog posts or social media?" Almost every image created in the last 70 years is still protected by copyright, but you can find a public domain photo, an image that does not need attribution, or image that has copyright expired. First, it helps to understand some copyright-related terms before using any free images. Always read the terms and conditions of the site you try to use to download free images and photos, so you know if, when, and what type of attribution is required. What is Creative Commons? Creative Commons is a nonprofit organization that enables the sharing and use of creativity and knowledge through free legal tools. There are various types of Creative Commons licenses that range from allowing any type of use with no attribution to allowing only certain uses and no changes. Most authors using Creative Commons require some sort of attribution. While relatively easy to use such free images in blogs, using such images for video might be problematic unless you create lengthy credits section. Even if you do, you still may breach the particular image Creative Commons license since it often requires backlinking. What is Public Domain? Works in the public domain are those whose copyrights have expired or never existed. The public domain status of official government works is sometimes difficult to determine but there are some easy cases: works of the United States federal government, for example, are not protected by copyright and are thus in the public domain. The same does not hold in general for the works of other governments or all 50 States of the United States. Determining whether a particular work of a particular government are in the public domain requires research and sometimes even legal advice. What is Royalty-Free? Most royalty-free images aren’t free. In most cases, you’ll have to pay a one-time fee to obtain the rights to use the image. Then you can use it as many times as you like. The term “free” in “royalty-free” means that you do not have to pay royalties to the owner of the image every time you use it. We've reviewed terms of few popular Free Image Websites below. 1. Unsplash Unsplash has its own license, which essentially lets you use the images for free, in any way you like, except for using them to create a competing website. 2. Pexels Pexels also has its own license, which states what you can and cannot do with the images. You can use and modify the images for free for both commercial and personal use without attribution. 3. Pixabay We love Pixabay. Images on Pixabay are licensed under Creative Commons Zero (CC0), which means you can use the images without asking for permission or giving credit to the artist. Pixabay also explains tricky legal language such as "model release". 4. Gratisography Gratisography also has its own free photo license, which lets you do “almost anything you can think of”. While they have not too many images, many are high-quality images that I would use. 5. Flickr Flickr is where you can find images that can be used and modified for commercial purposes. Select “Commercial use & mods allowed” under the “Any license” filter to find those images, and remember to check the license for each image as they vary. Be careful with Flickr images since as far as we can see, many images are labeled public domain wrongfully or without much research. 6. Google Image Search Google Advanced Image Search is a method of finding free-to-use images through Google’s own search tools. It is 100% automated, so you can't blindly trust the license cited. Use it with caution. Same as Flickr, Google bears no responsibility. When using free online images, always do your research.

World War II was a period of rapid technological advancement in the field of aircraft, and these advancements have continued to shape the development of aircraft in the years since. There were significant advances in aircraft design, such as the use of swept wings and the development of more advanced aircraft materials, such as aluminum alloys and plastic composites. These advances allowed for the construction of stronger, lighter aircraft that was capable of higher speeds and greater maneuverability. Biplanes, which have two main wings stacked one above the other, were largely obsolete by the time World War II began in 1939. They had been largely replaced by monoplanes, which have a single main wing, by the start of World War II. The main advantage of monoplanes is that they are typically faster and more maneuverable than biplanes due to their streamlined design. In addition, monoplanes are able to carry a greater load for their size, making them more suitable for use as bombers and transport aircraft. However, biplanes were not completely abandoned during World War II. Some biplane designs, such as the British Hawker Hurricane and the Soviet Polikarpov I-153, saw limited use as fighters. In addition, biplanes were used in a number of other roles, including training, observation, and light transports. One of the major developments in aircraft technology during World War II was the use of jet engines, which allowed for faster and more powerful aircraft. The first jet aircraft, the German Heinkel He 178, made its first flight in 1939. However, it was not until after the war that jet aircraft became widespread. During World War II, a number of aircraft were produced in large quantities to meet the demands of the war. Here are some examples of some of the most massively produced aircraft of World War II: The Soviet Union's Ilyushin Il-2 was a ground attack aircraft that was produced in tremendous numbers, with more than 36,000 being built. It was heavily armed and armored, making it a formidable opponent on the battlefield. The German Messerschmitt Bf 109 was a mainstay of the German air force and was produced in large numbers, with more than 35,000 being built. It was used as a fighter, interceptor, and ground attack aircraft, and saw action on many fronts during the war. The American Republic P-47 Thunderbolt was a heavily armed and armored fighter that was produced in large quantities, with more than 15,000 being built. It was used extensively in Europe and the Pacific and was known for its durability and long range. The British Supermarine Spitfire was a highly regarded fighter that was produced in large numbers, with more than 20,000 being built. It saw action in many theaters of the war and was known for its agility and handling.