After you’ve logged in, click your name at the top-right corner and choose Edit Profile from the drop-down menu. Here you can update your name, email and password.
For security reasons you will need to enter your current password before you can choose a new one. If you don’t want to change the password simply leave the password fields blank.
Your profile photo is pulled from Gravatar based on your email address. If you don’t have a gravatar account or prefer not to use it simply choose the Default option in the profile photo setting. This will show an auto-generated image of your initials.
If you wish to disable profile photos altogether you can do that from Settings > General.