Can someone tell me if there is a way to add "Text Only" attribute to a skin ?

You mean you don't want any CSS, or do you want to hide the images people eventually add through the CMS?

That you could solve with:

img{

display:none in the skin

}

You might need some extra selectors.

You want to get rid of the default CSS DNN loads?
e.g

-default.css

You can only do this with a skinobject as Sebastian decribes.

I have developed one that prevents the loading of default.css.

I still have to do some testing (and some other work before)

You could also edit the default.css file, but it will be overwritten with every update of DNN.

The CSS I posted should just be added to the skin.css file.