Actually, you can install openSuSE from an ISO image. You need to give the location of the iso which could be in a directory or a samba share. The trick is booting the installer.
If it is located in your home directory of your fedora installation, that would be fine.
Mount the iso and look at the install pdf in the /docu/ directory. Look at 1.2.1 for instructions on booting with hard drive.
Hard Disk openSUSE installation can also be booted from the hard disk.
To do this, copy the kernel (linux) and the installation system
(initrd) from the directory /boot/architecture/ on the instal-
lation media to the hard disk and add an appropriate entry to
the existing boot loader of a previous openSUSE installation.
So you could copy these two files from the image and add an entry in /etc/grub/menu.lst or bootup, and enter the grub shell. Then enter a "kernel ..." and "initrd .." line. Then enter the command boot. You can use tab completion to enter the files you copied to /boot/.
After booting you can select the ISO file as the installation source.