We apologize for the interruption. The technical team is aware of the issue you're experiencing while uploading profile pictures and is working on fixing it as soon as possible.
UPDATE as of 15-JANUARY:
Thank you for your patience, everyone. This issue should now be fixed. If you continue to experience the issue, please try basic troubleshooting steps such as clearing your cache and cookies. If you need further help, kindly reach out to the Upwork Support team to be assisted further.