Getting free and relevant Images ( / APIs) for Product/APP/Website/Blog

While envisaging a new feature for one of our web product where customers can choose any set of relevant pictures from their categories to build a proper GUI on their own, we consume an APIs provided by various awesome companies to list down various images under any categories given. Was amazed on the quality and speed.
On second incidence, was searching for the correct images for my blog. Searching for a perfect image on google, landed up in various websites to use (with copyright, with CC, etc.).
Hence listing down major free and Paid websites I gone through from where we can get License free Images ( / APIs ) for your product / app / blog.
Free Websites
UnSplash
Awesome website with Free Images & Pictures. You can download and utilize the images for free. It’s highly recommended to give credit to original author but not mandatory. Medium article images would also came from Unsplash (just figured out while writing the article.)

If you are a developer and want to get the APIs to fetch the Photos run time for your project, this is the best APP to go ahead with that. [ https://unsplash.com/developers ]

Pexel
Great website with royalty free images and Pictures. You can download and use for commercial & Non-commercial views. In return you can tweet, donate or follow the author on Instagram if you want but not mandatory.

If you are a developer and looking for an API from where to get the Pexel images for your images functionality. Use API documentation to easily load images.

Pixabay
Another website where you can get a lot many awesome photos of your wanted categories for free. [ You need to SignIn to download high resolution images ]

Pixabay also having an API access to incorporate the stock photos in your Product/App.

Paid Ones
ShutterStock
Very popular one and source of very cool images. It’s a Paid if you want to download without embossed watermark.
This is the best one if you don’t bother on the embossed watermark come with an Image.

Adobe Stock
Awesome creative pictures to download. You need to pay Adobe license fees to download the same.
If you need just few images for your webpage, get your first 10 photos free.

To get on the developer API, need to create a Adobe CC account. It’s paid version and based on the need, pricing would be changed.
Other than above, there are lot many websites which we can google around on free and paid images ex. GettyImages, Dissolve etc. but seems that not as cool as the mentioned one as per my understanding.
