how to add images at runtime in textbox in asp.net web form

Question

currently i am working on professional networking site in which i have one module called as articles, which accepts articles from its user and post this article to his profile.

For this purpose i need to create a text box which accepts data from user, data may contain text, images or only text.

i have no idea how to do this anyone know how to do this please help me

thanks in advance