I think it may be a glitch of some type because it has been doing it to me too. Before I could upload them no problem, and now it won't let me change the picture at all even after hitting crtl R multiple times and the picture size and type are all correct.
I don't believe this was asked yet and you didn't seem to mention this but when you are trying to upload the picture and when you are on the site are you using a phone, tablet, or a computer?
Some phones and tablets naturally have a issue with uploading pictures in a different format than what it was originally.
If you are using a computer, as someone else has mentioned, try control+r to refresh it and see if that works. Macs are command+r I think.
Also, what browser are you using? That can help us help you further.
I don't think it's a glitch on the site itself but it's a possibility.
Since you have said it is in a jpg. format it shouldn't be much of a issue to fix.
Have a blessed day! :)
My take on this will be: That there could be a time delay implemented before the profile picture updates. Time Delay gives enough time for the pictures to be reviewed if they are within the metrics specified for pictures. This is to aviod people getting offended.
My thoughts on this if no Time Delay is implemented: If there are people experiencing the same problem then there is indeed a problem with the process of uploading pictures.
If the browser is a cause: It is advisable to always download the latest patch for your browser all the time. There are many functionalities that can be restricted in some websites if your browser does not meet the requirements specified for the functionalities to work such as uploading pictures and running features that were created using latest tools. There are risks as well for your account if you use one which is considered "sunset." To avoid your personal accounts to be compromised best you update your browser immediately.
If the problem is with the picture format: Try another picture and see if it will push through.
If all else fail. Try changing your photo after 24 hours and see what will happen next.