DAZ packages the JPEGs because Poser can convert them to BUM format, Pro Pack can use them directly, and we can edit the JPEGs in a paint program. BUM files don't compress as well as JPEGs, plus they aren't really suitable for editing due to the conversion process. If DAZ included the BUMs in the package, the filesize would double, and people on dialup would be unhappy with the increased download times; despite the increasing presence of broadband, most Internet users are still on dialup. If DAZ distributed the BUMs alone, we couldn't easily modify them.