Block Copy size limit

[#1]

After moving to 10.5.8 my image is now just over 8 gigs compressed. Unfortunately, it looks like its now too big to block copy onto a 40gig
hard drive (eMac). The image itself, once laid down, only uses about
16gigs. Whats the limitation here? Why does block copy require so much
extra disk space?

Chad

[#2]

Its just over 16 uncompressed. So if it takes 8 to store and then writes
16 thats only a total of 24. Seems like a 40gig drive would be okay.