The size shouldn't continue increasing like that though - WinRE.WIM is the recovery environment boot.wim, it's not the actual restore image, and as such it should technically not be growing at all (and neither should the recovery OS .wim file either, technically - these should be static!). It might be useful to see what is writing to WinRE over and over to cause it to get so large (it would have to keep being remounted).
Creating a WinRE.wim and configuring it as the recovery environment also requires the OPK, so this machine is likely an OEM machine with an OEM image of Windows on it. Care to specify which make/model it is, so we can do some investigation there as well? You haven't filled out your system specs, so we don't know at the moment.