Detailed instructions are here, from which the basics are:
Add an image
- Open a document, spreadsheet, or presentation in Google Docs, Sheets, or Slides.
- Click Insert and then Image.
- Select from the following options:
- Upload: Choose an image from your computer and click Open.
- Take a snapshot: Use your webcam and click Take a snapshot.
- By URL: Paste the URL of an image from the web and click Select.
- Your albums: Choose an image from one of your photos albums stored on the web and click Select.
- Google Drive: Choose an image stored in Google Drive and click Select.
- Search: Choose an image from the stock photography archive, or the Google and Life archives, and click Select. Your image will be added to your file.
Image size and format requirements
Images must be less than 50 MB and be one of the following file types:
.gif .jpg .png
There is also a video.