First, changing to AddComponentProperty has nothing to do with the issue, which is that the control(SelectButtonWidgetImage) is null.
Second, ofcourse I'm using sitefinity or rad control for this field....it's your own designer wizard.
Third, that blog post is from 2 full versions ago, and uses different types altogether. The ones done in the designer are LinkButton, not ImageField. Is there nothing I can find that is relevant to the current software? A large reason I'm even using sitefinity for this project is because this stuff is supposed to be built in. I'm not interested in building my own designers. The documentation for everything regarding this product is frustratingly sparse to say the least.
Am I wrong to assume that someone inside your team would replicate what I'm doing? It seems like most responses to everyone just points them to years old blog posts.
Part of what makes this product so hard to use and debug myself is that the intellisense is basically non-existent, so I can't even look through object properties to see what my options are.
I'm using Visual Studio 2013. Please make an MVC widget with just one field using Guid as the field. Create the designer with Thunder and use Image Selector as the field type. Then let me know why the designer is not working please.