Be sure you have the LDS Tools app installed on your mobile device and that you have your LDS Account login (Same one you use on LDS.org). If you have not created an LDS Account login, you may do so at LDS.org (be sure you have your name, membership number and confirmation date).
2. Go to your record.
a. This can be done by scrolling through the directory then clicking on yourself, or
b. by clicking on the menu in the upper left (3 horizontal bars)...
...then by clicking on your name at the top.
Click on the edit button (often a diagonal pencil in a red circle in the bottom right).
Select Photos, then click on the existing (or non-existing) photo.
Click on the Camera icon.
a. You may either select a photo already in your device photo album (click on "Select Photo"), or
b. You may take an immediate selfie by clicking on the "Take Photo" option.
After selecting "Take Photo", your device's camera app is opened. You may then take a photo of yourself ("selfie").
Click OK. This will then take you back to the Photo page.
This should take you back to the Edit Information page, then click on the checkmark in the upper right. This saves your changes and you are done!