How can i put my photo as my profile pic?

Yahoo is in process of changing the profile page,
changing over to account page, and they decided to put nickname posting and picture
posting on hold for now. Not sure when it will be allowed again, if ever.

https://yahoo.uservoice.com/forums/219007-us-membership-desktop/suggestions/7144519-how-do-you-change-your-picture?tracking_code=99a33dab4ca0d61f7221d7619a8f4e32

You can't. Avatars and the editing of nicknames have been disabled. They are making changes to profiles. No one knows when or if they will be enabled again.