NetBackup compressed images and upgrade from 7.1 to 7.5

We are planning to upgrade from NBU 7.1.0.4 to 7.5.0.6

Catalog compression is enabled for NetBackup, we have a 190GB drive using about 100GB of space for the images, however the uncompressed size of the images is close to 230GB.  My concern is that if the upgrade uncompresses these images we will run out of space, so my question is; does the upgrade process uncompress these images? 

Many thanks

Keith