All users should have the same permissions to post images using these programs. I am pretty sure that there aren't any personal or post count restrictions.
You have to use one of the add-ins that allows you to post images, like HTML Maker or Excel Jeanie. There is a Sticky in the Excel forum regarding HTML Maker. There are some threads in the About This Board forum that talk about HTML Maker and Excel Jeanie and issues that people have encountered.