I extracted it into the sourcemods folder, inside SteamApps, same drive, and still not showing up. I used 7zip.
You need to upload your image somewhere (imgur/gyazo/whatever). The path to the picture on your hard drive is not enough (we can't see it). Is the client.dll in "your_steam_dir\SteamApps\sourcemods\tf2classic\bin\"? Are you looking in Steam for all Games?