Making backups from personal files is relatively easy. System files sometimes have the nasty habit that they are inaccessible during backup when they are opened by the operating system.
An image of a disk is a compressed 1 to 1 copy of all the information on a hard disk. The image is stored in one large file or in a number of smaller files and you can copy that image back to a new hard disk in case your original hard disk crashes. Images are large, often several gigabytes, but their advantage over regular backups is that they contain a complete copy of all the programs, settings, data etc of the disk. With an image you can restore a fully functional system in some minutes to less than an hour. Because image files are so large they are not usable for daily backups or for transfer over the Internet to a remote host. A backup practice used by some people is therefore to make a new image only after significant changes of the disk, for example after the installation of a new program and use regular file backup schemes to store changes since that image creation.
Free doesn't always mean bad or not-supported. Some free solutions have great support of the on-line community where you can have your questions answered in minutes, rather than digging yourself through the support system of a commercial organization.
I must admit that for my own backup I still use command line FTP utilities embedded in script files. Great for the geek, but not so for the average computer user :(. That's why I don't have much experience with the more user-friendly FTP backup solutions. I hope that other members can input their experience with FTP backup solutions here and help you in the right direction.
Just one rule: Mentioning of products is allowed in this thread, but no promotional campaigns please.