[Sigma Tha Kid]

How can you install themes that don't have manila content? For example, I found a theme that I thought very cool. It said it had all the files needed, which they were zipped. I extracted all the files, and they were wallpaper and another one with just Microsoft flag on it. Now, there have been a couple of themes I was able to load. Like the Hellboy theme and throttle launcher (Very kick-***), the O2 theme and the Vodafone theme. These themes were either .tsk or .cab files. These files were associated with the manila files, but I've seen themes that were extracted from a zip file and had all the manila file folders but no .tsk, .cab or even that strange .rar file. Can anyone help with this issue?



PS
On occassion I have seen .rar files, which I'm not too familiar with. What are they?