Hi.
You can try something like this
<%
data p_image type ref to cl_htmlb_image.
data: p_image_string type string.
create object p_image.
p_image->id = `PDFLink`.
p_image->src = cl_bsp_mimes=>sap_icon( `ICON*` ). "Put your image
p_image->tooltip = ``.
clear p_image_string.
p_image_string = p_image->IF_BSP_BEE~RENDER_TO_STRING( page_context ).
%>
<htmlb:button id = "PDFLink"
encode = "FALSE"
text = "<%= p_image_string %>   <OTR>your referenced file</OTR>" />
Hope to help