I am trying to modify the basic installation environment (ie, what Anaconda runs in) for a customized CentOS distribution.

For the first try, I would just like to modify a few of the splash images.

My initial attempt to do this entailed:

1) Mount images/install.img to a directory ~/img/
2) Copy all files from img/ to ~/tmpimg/
3) Modify the splash images
4) mkisofs -o ~/final/install.img
5) cp ~/final/install.img back to my ~/cdroot/ folder and remake the iso.

However, the generated .img in step 4 doesn't even come close to matching the file size from the original install.img (meaning that install.img must be created in some other fashion using compression), and it fails when I boot my iso.

What settings should I be using to make the install.img file? Is there some other technique for modifying CentOS install environments?