Given the history, and the fact that these are probably not replaceable, I strongly suggest getting Slacko, you download it as an .iso file then burn it to a disk, then you boot to this in your DVD drive, it is a Linux operating system, and it runs from your ram, it does not install or attach itself to your hard drives, so it will not alter anything you already have in place, but it will allow you to access the drives without the possibility of other influences, such as remnants of the infection, as I am concerned that this could be given it wants to access a program you have not asked it to ?
Now with this program loaded, you can access the files without hindrance, navigate to find your pictures, and save them to your PC's hard drive, NOT the external one, also move any other files to be kept at the same time, once saved reboot to your normal OS, then format the external drive, this will remove the hidden files on that, then you can move your files back over again, with luck this will get your files and stop it from doing it again.
What I strongly suggest is you save these, and ANY other such files that you can't afford to lose, to another location, I am not saying don't save them to your external drive, I'm saying save them to more than just your external drive, if you can't afford to lose them, then a single back up source is not wise, if one fails you always have another one for safety, so either burn to disk(s), and\or upload to an online repository, PhotoBucket is great for saving pictures, but many prefer other similar sites, you can sign up for a free account, create a folder(s), and upload them to there.
The most important note here is lock the folders (make them private), that way no one can see or access them without first having the password that you create while securing them, that way you minimise the risk of losing them, just incase this sort of thing happens again, hardware failure is not to be ignored, a drive can die without notice, this is why you should save in more than 1 place\format, it's not just infection you have to consider.
Now I'm not sure how used to using Slacko you may be, my guess is you've probably never heard of it before, in which case it will seem like a major learning curve, but I am the same with Linux, yet I can use it for this kind of purpose, so it's not to hard, the drives are listed across the bottom left corner above the start button, clicking them you can view the files on each, you do so by "mounting" the drive(s), so just like windows you can copy and paste files from one drive to another.
You will also need to set some variables such as screen size, and language etc, no different than windows the 1st time, so have a play and see how you go, then ask about any bits your unsure about, and we can try and guide you there.
There are many versions of Linux, if your more comfortable with a different version then use that, but it's probably the safest way to start as it does not directly touch anything, as long as you don't delete anything, everything will be the same when you reboot, only you will have the rescued files as well, just make sure you know where you save them to, hope this helps a bit.
