well, I'm not sure if it works on a mobile device - I think you have to be on the full-site on a computer or laptop
At the top of your screen (top right for me) there is a series of "commands" and one is labeled SETTINGS
When you click on that, it opens a page for your profile.
On the left side there is a box called "My Settings" and one of the commands there is EDIT AVATAR.
That is the one to use to add a profile image.
Then I think you follow the instructions on the screen to either upload an image from your computer or link to an image URL. Some images may not work, if they're too large for example.
I can only guess what kind of image would represent the Jazz Wonderbra.
By the way, the wonderbra was developed by someone named Moe.