I have set my default thumbnail size in settings > media, however as I see it you Have to add a value. However, I'd like to specify a width, but allow for an unrestricted height. For instance, both these dimensions would be alright:
w: 120px h: 70px
w: 120px h: 240px
Doesn't Wordpress allow this behaviour? Or should we simply set the height value to a ridiculously high number?