This is not true, or the case.
The images contained on http://dietpi.com/download are the default DietPi net install images. Software is installed on demand via user run dietpi-software.
The images contained on https://dietpi.com/phpbb/viewtopic.php?f=8&t=2317&p=8869#p8869 are the pre-installed, ready to run Allo GUI images. These contain all the software as described in the information link below:
https://dietpi.com/phpbb/viewtopic.php?f=8&t=2317