Hello everyone,
I am very new to regex and i can't seem to make it work for my issue, but i think it might be the right solution.
I have a column with image sizes that look like this

and i would like the end result to be just a column with the sizes as so "320x50" , "1200x250" no matter if the sizes are
I put the file sample in 
if there is a way to do it without regex its good too
thank you so much for your help
Nouha