what images do grumio and curtis use in theirbanter/ why are these images chosen?

There is a lot of cold and hot imagery. Yes, they are trying to start a fire but the cold and the hot imagery is meant to reflect Katherine the shrew. The cold also reflects the sense that the shrew (katherine) can be somehow tamed,

"She was, good Curtis, before this frost. But thou knowest winter tames man, woman and beast..."

Grumio also says that Petruchio is as "shrewish" as Katherine if not more.