Pickit is another image resource site, but it is uniquely focused on providing images for PowerPoint presentations. The home page boldly says “Legally Cleared images for people at work. Make your work stand out with unlimited access to royalty free photos and clipart in PowerPoint.”
Pickit
To go with the PowerPoint (and Word) focus, Pickit has a Microsoft Store add-in that provides quick and convenient access to a large library of royalty-free and legally cleared™ images directly inside PowerPoint (and Word), meaning you can use them all without worrying about infringing on copyright laws. 

To install the add-in go to INSERT > STORE > search for PICKIT > ADD.

Pickit

Access the image library any time by clicking the PICKIT IMAGES button on PowerPoint HOME tab.

Pickit

Open the Images action pane, search for any image, click INSERT, and the image is added to the current slide.

Pickit

There is a free version that accesses the image library only from PowerPoint (no website access) and no HD resolution. The subscription is $1.99/month and makes all ad-free with unlimited app and web access, and access to HD resolution images.

Troy @ TLC