hi,

first question:

how can i disable a build-in module (Image) so the host/admin can't add a specific module from the dropdown box? (i've the source code)

second question:

i've 3 panels in my skin (left, mid, right), i want to make sure you can't select the left panel from the dropdown box just to make sure you can't add other content to the left panel.

1.
You can disable any module type for admins (but not for hosts) by making it a premium module (in host > module settings > edit module definition). If you don't want to use a certain module type any more at all, you can uninstall it.

2.
What content do you want on the left pane at all, and who (host, admin, page editors,... ?) should be able to add content there? If it is fixed content, then perhaps you can put it in the skin file and omit the left pane? Can you give a use case?