On the settings page, where it says: "Public Profile Settings - PROFILE PICTURE URL" there is a box.
In that box, you paste in the link to the photo you want to use.
To get that link you will need to go to wherever your image already exists on the internet, right click, and select "Copy Image Address" then paste it in
Hope that helps
I have done this from various websites... none of the links work in Steemit.
I have to download mine first to get them to work, then they go right up from downloads. Im not good with computers, but it's been working for me.
I lack an upload option ony profile set up page.