If time is short and you don't care to read on, go ahead and check out the app (on desktop or iOS) called "Unsplash". It's free!
Speech Pathologists who do language therapy (whether with adults or kids) are always looking for new material. Good photographs in particular are great for a whole host of targeted skills (inferencing, verbs, narrative skills, etc.). But doesn't Google images do the job, you ask? Yes, Google is great, but consider the following:
1. The organization you work for might not like you pulling images from possibly protected sources (even if you don't plan on distributing them to the marketplace).
That's where Unsplash comes in. Photographers from around the world upload their work for the world to see and download. All that content creators ask is that they are given credit for their work should you use their images for public consumption. But for average people like me who just pull awesome images for a vocabulary group- it's just one click and I'm done! No payments or subscriptions required. Your welcome!