While this is an old (and mostly answered) question:
To my knowledge (which could be entirely wrong, mind you!), TOSEC does _not_ maintain archives of the material (disks, CDs, DVDs), only the "meta data" about the material. (Excepting maybe the images/photos/scans of it, which TOSEC has the IMGs section for.) Sites like archive.org are more suited to preserving the material itself, while TOSEC is well suited to collecting only the meta data (_names_, check-sums, and other identification data, etc.) of the material.
There is a very fine line in the legal arena between the different parts -- Collecting meta data about something is not illegal and does not violate copyright laws, no more than writing down a list of our favorite song names o share with your friends is a violation of law. Making copies of the "something" itself, however, is at risk of copyright violations, even if you claim "preservation purposes". Using the songs example again, making a copy of the song itself and sharing that is a legal copyright violation.
As for making the actual digital dumps... It varies. For floppies, as long as there are no _intentionally corrupted_ disk sectors (done as a form of copy protection) or some such, there are many imaging tools you can use, besides WinImage. Some are high grade and can attempt to recover corrupted (from age, not intentionally corrupted) sectors, while others will simply place invalid data in those sectors, and others still will simply "zero fill" any it could not read. Some are just software, and others are matched hardware and software designed specifically for making dumps.
I will assume you are on Windows[tm], and not about to spend money for a "pro" rig. You can probably find a Windows[tm] version of "ddrescue" (Google found one on SourceForge), which does a decent job of imaging many minor corrupted disks. Or, you can set up a fairly cheap/low end older PC with a Unix/Linux OS and do the imaging from there. I have an _old_ (as in around late 1990, early 2000) computer running (modern) Debian Linux 9 for imaging and "old school" purposes. (I personally started doing this kind of thing with my first computer, an Apple IIc, in the mid 1980's.)
You can also find USB 5.25 inch floppy drives, although I do not have info on how much they cost. (The real trick is finding an 8 inch floppy drive, or a Winchester hard drive controller...)