Unfortunately tinymce advimage plugin does not provide any extension point that you could use to extend the list of image properties.
The only possible way I see is to create a new plugin that extends the default advimage plugin, add your extra stuff to it and use it instead of the default one.
Thank you for your reply. I don't currently have any Episerver source code. I believe everything is packaged into .dlls. Sounds like I need to break into the dll if I really want to pull this off? Am I understanding this correctly? Thanks.
Actually it's not packed into dlls but into a zip file that you can find in /modules/_protected/CMS/CMS.zip/Util/Editor/tinymce/plugins/advimage/js/image.js
You could add another plugin and turn in on in EPiServer admin mode.
Btw. what do you mean you don't have the source code? It would be hard to upgrade without the source code ; )
Yes, I misspoke. We do have the source code.
Hello. I have a request to modify the TinyMCE editor and I don't think the TinyMCE Custom Editor can help me. When a user clicks on the Insert/Edit Image Button, a dialog window pops up that allows the user to enter attributes for the image. What I need to do is add additional fields on that dialog to insert custom attributes for that image. I don't currently have Episerver source code so am wondering if there is another way to add additional fields to the dialog or extend it somehow so I don't have to remember to update this code every time we do an Episerver upgrade. Thanks.