You can upload a Profile photo via...
Via the app:
Select the Profile icon > Smaller Profile icon > Edit Profile and Privacy > Tap the Profile thumbnail and follow the prompts > Save.
Via the website:
Sign In > My Account > Edit profile > Change Profile photo > Update.
If you wish to upload a Profile photo using the app, please ensure you have allowed the app access to your photos through your device settings.
iOS: Launch iOS settings > Privacy > Photos > Locate Insight Timer.
Android: Launch Android Settings > Apps > Locate Insight Timer > Permissions > Set Storage Toggle to 'On'. (This setting may vary depending on Android device).