1. How do I disable Text Selection for a certain module?

In the module settings, make sure "Disable Text Selection - SPECIFIC AREA" is checked. Find and insert the DIV ID of the module in the "Text Selection DIV ID" box. For example, a module with moduleID 503 will have a ID like dnn_ctr503_ModuleContent

2. Why can I still click on some images even though the module is configured to disable right click on images ?

The module will only disable right click on images that have an <img> tag. In other words, it will only disable images that have been added explicitly to the page using modules or other direct means. It will not work with images shown through CSS, iFrames, etc...