youtube thumbnails are too big in Firefox 47.0

[MasterofLego]

i have a weird problem, the other day my firefox updated to 47.0, and now the thumbnails on youtube are so big it is only three thumbnails wide, but when i open youtube in private mode, it looks normal?

pics:
http://imgur.com/a/kDM8E

might try burning the cookies lol

 

[MasterofLego]

clearing the cookies fixed the problem.

 

[Colif]

I hate it when you work out the solution just after asking for help