Can't edit Alt Text in Images (Teaser Box Visual Composer)

I have 3 teaser boxes (Visual composer) set up on a page and realized that the Alt text does not transfer to any image used in these boxes. The Alt text for each is simply (Teaser Image).
They may be seen at http://www.gandgcriminaldefense.com/

I have looked for a CSS edit but cannot see one, is there a way to edit them out of CSS or would this require me to buy a license to get support from them?

Also can the Extensions be added from Visual Composer?

Thanks