Can't properly add an avatar

If you want to resize your picture, you have to use a desktop since you can’t resize your profile pic on mobile

You go to the drop down in the right top corner and click the "settings" option. You should see a place where it says "Avatar:". If you don't, make sure you are on the profile settings rather than activity settings. There will be a place to click upload and you will then chose a picture from your photo library. I may be that you have to reduce the picture's space. Like I think mine is 2 MB. Hope that helps.