If you are using Internet Explorer, instructional text in green should appear after clicking 'upload image' that reads: "Image uploaded. If your image has not appeared please refresh this page or sign back in."
If the profile picture doesn't update or display properly, try refreshing the page and/or signing out and then back in. Alternatively, try using a different browser, such as Chrome or Firefox.
Double check that the image is in a valid file format and does not exceed the stated size limits.
If you are still having difficulties after trying the above, submit a help ticket here or contact your system administrator.