Inserting an image into a document isn't rocket science, but there's a way to insert images directly from a Google Search while inside a Google Doc.
1. Open the Google Doc.
2. Click Insert > Image from the menu bar.
3. Click Search.
4. Type in your search criteria. You can select to search Google, Life photo archives or Stock Photos.
5. Select a picture and click Select.
This makes it so much easier for students (and teachers) to find images. You don't have to do a separate Google Search - you can stay right in Google Docs (or Slides, Sheet or Drawing).