Hello Ana,
Thank you for your response. I have checked out the link you have provided. We did not edit any files in sharepoint to get this working. The icons show up fine if we are pulling documents from couple of sites but in our production we are doing the roll up for 15-20 sites in a single web part(i.e web part is pulling the docs from 15-20 site collections). Then we are not able to get the icons working fine. Please let me know if it works fine on your side with data being pulled from many sites.
Regards,
PriyaSaki