<deploy_image>
<image_installation config:type="boolean">true</image_installation>
</deploy_image>
Those images are in the "/images" directory on the installation media.
YaST will calculate on it's own which images to use to fulfill the requirements in your <software> section. At the end, a system which was installed via RPMs only and a system that was installed by using images + some RPMS will look exactly the same.
I did a test with the following in my autoyast profile:
<deploy_image>
<image_installation config:type="boolean">false</image_installation>
</deploy_image>
<software>
<patterns config:type="list">
<pattern>base</pattern>
<pattern>enhanced_base</pattern>
<pattern>sw_management</pattern>
<pattern>games</pattern>
<pattern>imaging</pattern>
<pattern>kde4</pattern>
<pattern>kde4_basis</pattern>
<pattern>multimedia</pattern>
<pattern>x11</pattern>
<pattern>xgl</pattern>
</patterns>
</software>
the installation took about 25 minutes via network and 738 RPMs were installed - no images of course because the boolean was set to "false". The system was about 1,9GB in size.
Then I changed image_installation to "true" and did the installation again. This time it took about 13 minutes and besides the images, 114 additional RPMs (638MB) were installed. Those RPMs were not covered by the images and so they needed to be installed as RPM.
Take a look at image installation on your own with openSUSE beta5. Maybe you can speed up your autoinstallations.