To work with Joomla 1.0.12, here is what I had to do to get it working:
1. Download the com_securityimages4.1.2.zip file. The link provided for downloading from this site (extensions.joomla.org) goes to an invalid page and the webmaster needs to correct this. It does take you to the www.waltercedric.com site. From there, look for the downloads link, and then to Joomla, and then further to security. There you will find the com_securityimages4.1.2.zip file.
2. Install it from Joomla
You have to know to install it as a Component and not a module or mambot (plugin).
3. Once successfully installed, go to the Components --> Security Images --> Edit General Settings and then click on the Joomla Patches tab. Here you find that a patch must be loaded. Conveniently the provide you with a link for patch, but there is no listing of patches for Joomla 1.0.12 from their link, only 1.0.11 and earlier.
4. Installing a patch after the download
I did some rummaging and found that there is a patch for 1.0.12 on Walter's site at:
Running the patch through the Joomla installer does not seem to work. I examined the files and did a diff of the individual patch files against the installed files and found small differences in the code.
You could hand edit the files or just replace them with the ones in the patch distribution (if you are replacing the files, you would need to keep track of file ownership and permissions so that your installation is not disrupted). Needless to say, back up your files and take Joomla offline before making the changes.
There are many files that need to be replaced/modified and the directory structure of where the files belong is anything but flat. It is very easy to inadvertently clobber a file or two if you get distracted or are not careful.
After this is done, test your installation.
Although I had to jump through many hoops to do the install, it worked flawlessly upon the first install!
Is it worth it to go though this amount of effort for the convenience of security? Well, if you're in the business of hosting, security is everything.
I'm extremely happy I have this security tool. I hope there will be support running it on Joomla 1.5. I have not seen any indication of a new version in preparation. Hopefully, we;ll all be pleasantly surprised!