Pixabay is a repository of tons of images, all these images can be used for free and are licensed under Creative Commons CC0.
These add-ons let you :
• Search the Pixabay database without ever leaving Word/PowerPoint/Photoshop;
• Insert any image you like with one click;
• Stop worrying about licensing images!
All images are safe to use - paying attribution or linking back to the source is appreciated, but not required.