VERIFIED SOLUTION i

Can I add Smileys to Questionnaires in Portrait Dialogue

Smileys can be used in Questionnaires in Portrait Dialogue, but not as images.
To add smileys, you need to use the Unicode characters for smileys.
There is a web site here that lists Unicode emoticons and their Hex and decimal values. 

Portrait Dialogue Questionnaires are generated at run-time.
All the components are stored in the database there is no HTML page to directly modify.

However, all the pieces created in the editor can be entered as HTML Code.
It is possible to enter a Unicode smiley character and modify the font size to get the right look. 
Using the HTML decimal or hex code for the appropriate smiley will display it.  

The images below explain the process.
In this example, the HTML code for an unhappy result is entered into the column text area in the matrix properties.

User-added image
User-added image

The end result is like this.
User-added image

 
UPDATED:  October 15, 2018