Hi - I'm fairly new to Salesforce and am looking for help with icons not showing in my visualforce page.  If you see the screenshot below, most of my icons are not displaying for some reason however one of them is.  Can someone help me figure this out and/or point me in the right direction to troubleshoot?  I'm not sure where to look. 

Thank you!

Hi - I'm fairly new to Salesforce and am looking for help with icons not showing in my visualforce page.  If you see the screenshot below, most of my icons are not displaying for some reason however one of them is.  Can someone help me figure this out and/or point me in the right direction to troubleshoot?  I'm not sure where to look. 

Thank you!

  How would I go about doing it?

The usage is as follows:

For example, if an account has 10 contacts, instead of editing one at a time. I want  to be  able to display a table of  with just First Name, Last Name, phone, e-mail, Title

The dataTable object - is there any option to create an editable grid?