One of the best platforms in gaining copyright free images for use away from the platform is Pixabay. A superb source for images of for just about any topic imaginable.
Pixabay in excess of a staggering 2.5m images, so you’ll never really be stuck for choice regardless of what your subject matter is.
There are other platforms who offer similar things and includes Pexels and Unsplash, so there are tons of opportunities.
If you want to avoid captcha codes with Pixabay then, all you need to do is give them your name and email address which is optional.