Yeah, you can do that with a template edit. Just create a new profile field. (
AdminCP ->
User Profile Fields ->
Add New User Profile Field) Make whatever kind of field you want. If you're going to have like a Yes, display the image or No, don't display the image kind of deal. Then I'd make Single-Selection Radio Buttons. Then after you fill out all the details and submit the field you need to find the Field Number. It's in the name column of the Profile Field Manager. Then just place this code wherever... in your case you said you wanted to display something on your index, so you need to put it in your FORUMHOME template. Just replace the
xx with your field number.
Code:
<if condition="$bbuserinfo['fieldxx']==Yes">
If you selected "Yes", then you can see this message! Isn't that wonderful?
</if>