The developer image can be re-sized pretty easily as well to accommodate for larger space for building if needed.
You can also make a new blank VBox image in the size of say 50gigs or whatever you’d like, then in the VBox machine settings set the developer image as IDE and the blank image as SATA, and choose GParted-Live as the cd.
Boot from the GParted-Live CD, and choose the developer image as the device, and right-click and copy the farthest left partition, then choose the blank image as the device, and right-click in the unallocated space, and choose paste. Do this for each partition working your way right.
Then if needed, re-size the partitions to your liking, then click apply at the top, and wait a long time. It took quite a while to re-size the 4gig developer image to a 50gig image, making each of the partitions around 12gigs each, completely unnecessary I know, but just wanted to see if cloning/re-sizing the image would still boot, and it does.