Webinar wallpaper gets pixelated

Today I am trying to set a new webinar wallpaper, but every attempt the image gets 'compressed' and pixelated on the preview, practice session, for hosts and for attendees. In the past I had no issues and I still a have a previous wallpaper in perfect sharpness which I can select from. No different process was made, even when I try to upload the same picture which I had uploaded in the past (before the last big update) it gets pixelated.