The topic icons are setup in the \'Topic\' link under \"Admin Only\" block.
Your icons are broken because you uploaded them as text files. Images must be transfered as binaries.
The best way is to have the permission to logon to your web site through SSH, but some webhosts are reluctant to give it to you because of the security risk.
I guess you used a FTP program. What ftp program do you use?
You can transfer the image directory again using Binary.
I recommand SmartFTP, with which you can rely on auto upload.
Sam