$content_width not working

Hi

I am trying to reset the $content_width variable as per the codex

In my functions.php I put $content_width = 2000;

I am then creating some new images sizes for the media library. I know these images are uploading with my new sizes because I checked with ftp and the filenames are correct but they are displaying wrong in the media pop up for images sizes and so the width settings are wrong int he code. This is exactly the problem described in the codex but the solution, at least for me, isn’t working

Can anyone help please?

E