To be able to add or change the profile picture on your Coins.ph account, you would have to link your Facebook account to your Coins.ph account. Once it is linked, the profile picture on your Coins.ph would sync with your Facebook profile picture.
Connect your Coins.ph account with your Facebook account by going to your Limits and Verifications page. Scroll all the way down to the bottom of the page to see the social accounts you can link with your Coins.ph account.
Then under Facebook Connection, click “Connect”: