If you a new user to steemit this article may answer some of your questions you have been wanting answers to.
Profile Picture:
When you are on the home screen of steemit (where you see your feed) hit the circle right next to post. When you go to that circle it should show a drop down menu.
After you see the drop down go to the settings button.
At this page you are able to make your about info, profile image, select language, and add your website.
Go on google and find the image that you want. Select the image and open it into a new window. Copy the url in he website bar and copy in paste it back in the steemit settings.
If you have any questions I will be able to answer them instantly within the next 25 minutes. So comment if you have any questions. Up vote this short article if it helped you in any way.
Good luck as you begin your journey through steemit.