The help video shows you how to upload to a photo to a Staff profile, the help text explains how to upload one to a Client profile. The steps for both are the same.
To upload a client’s photo click on the client's name you wish to add the photo to, then select their Profile tab.
In Edit mode, go to "Upload new photo” and click “Choose File” (2) to select the photo.
This will probably send you to the document library of your computer. Select the photo from where you have it saved on you computer.
Then, click “Upload now” (3).
Once the photo is uploaded, press “Save” (4) button.
You will now see the photo has been uploaded (5).