how to achieve (popup OR extra image)

[Harm10]

I guess you need to define a template that has 2 columns. Put those definitions within a subweblog. Use separate classes to divide the 2 columns over the page (e.g. width 30% and 70%), let them float left, define your extraimage in the left column, put your entry introduction/body in the right column, put a div below it that has a class with clear:both (so the next entry will not interfere with the current one). So it can be done. But you need to do some template defining yourself.