Hello! If you mean that you have successfully uploaded a picture that is displayed on the sidebar when clicking on a person, but not on the tree itself, first click on "Options" on the menu of the bottom of the screen.
Now you see a lot of boxes to check or uncheck in regard to what info is displayed on the tree - places of birth and death, middle names, born vs. current surnames, career etc. If you check the "Photo" box, any picture uploaded is displayed when viewing the tree.
Hope this helps!
