Winx DVD Ripper Platinum, WR, is one of those applications that appear again and again on giveaway sites - I wrote amply about this in my Software Trial thread, and it's understood that WR is devalued by that, but it's "for the masses/young people" anyway, so...
But while it's true that you don't really need WR - or similar, for that, but WR is free again and again, so... -, it can come really handy, and while dedicated giveaway sites (sharewareonsale, giveawayoftheday) don't let you know what's their freebies coming soon, WR for free (again!) is announced on bitsdujour, so monitor that site for the very next days for it if you haven't got it already on innumerable other occasions.
Why does it come handy? Well, perhaps you continue to watch DVDs - I've had that subject in other context in said Trial thread very recently -, and here and there, there is some stunning frame in some film - I personally I'm very enthusiastic of the very best cinematographers (the directors of photography in film), but in other films, you'll encounter such stunning frames too, just not so often.
Now the photos from a film - which you can get from google for some of them - are not frames from the roll, but they employ special set photographers in order to take them with their own equipment, for them, the stills, becoming much sharper and of better quality overall, but by this parallel working, these real photos rarely replicate the very best frames, so there is an interest in getting them from the roll, notwithstanding their lesser quality, technically-wise.
Now there's ffmpeg (free anytime), but I've got a problem with that (very powerful) command line tool. Often, DVDs are copy-protected, and then (only?), their DVD comes with lots of different files, and it's all a mess there and anyway, I didn't grasp yet how to do the necessary format translations in ffmpeg from DVD files respectively of just the relevant moments in them. ffmpeg (there are alternatives, but there's quite some help available for ffmpeg, so I use that one) cannot extract stills from the DVD format, but needs an (almost any) intermediate format to extract them from, so it's a 2-step process, and, as said, I have problems with getting the relevant seconds from DVD to the intermediate format, in ffmpeg.
Enters WR. In some video player, I simply note the time such a frame I want to get as a still appears, let's say -/+ 5 seconds, which makes it around 150 frames to get the needed intermediate format, then to get to single frames. Then, in WR, I select just those seconds for conversion, for example into the .avi format; here, WR very thankfully does all that work behind the scenes to scrap it from the DVD files: it does do exactly the part I'm currently unable to do in ffmpeg; of course, in WR, you'll select the highest possible quality (formats/settings).
Then, I just run ffmpeg with the right attributes, onto that (in this example,) .avi file, in order to extract the stills (frames, technically).
Some remarks: Some video formats don't do complete frames, but do frames as content differs from the previous frames; it seems that ffmpeg is able to re-build complete frames from aptly combining those partial frames again, just like your video player does, too.
There are some commercial applications which extract frames from the DVD, in one step, but the problem is not that they cost up to 50$, the problem is that they are just too bad as frontends to ffmpeg or some other free tool. The latter is just an assumption of mine, but that they are really bad is a fact, I trialed them all and took notes about their deficiencies.
Since with ffmpeg, you also can learn how good cutters do their cutting; here it's perfectly possible to (convert in MR some minutes, instead of just some seconds, and then to) extract 10,000 frames instead of just 150 or some, and then, for example in FS Image Viewer (free) or DO (paid), you'll get an incredible collection of quickly-browsable thumbnails from which then you can quickly distinguish any camera-movement, any cut, ready to further identify the transitions by looking at the full previews (both pic viewers, and others, have got a 2-screen mode), or you consider the "weights" of the (sub-)scenes, by counting the respective numbers of frames...
Now for the syntax; here I have to say that ffmpeg's syntax has changed over its versions, and that I use an old version of it, its new one not working with XP; this could be the main reason I had to give up in my tries to do the very first conversion, too, from within ffmpeg. But the following will help you to better understand (currently available) ffmpeg help, and to adjust to your respective use case:
as command, in command window or from other trigger:
C:\ffmpeg\ffmpeg.exe -i "C:\YourSourcePath\FilenameOfTheIntermediateFile.avi" -ss 00:00:00.000 -qscale 1 -vframes 2000 "C:\YourTargetPathWhereFfmegStoresTheStills\%04d.jpg"
-qscale 1 is "best quality", -vframes triggers the stills, 2000 is the number of frames you want to get exported, beginning with the indicated starting time.
The above would start from the beginning of the intermediate file; if you need your 2,000 frames (in my example) from minute 74, second 5 on, it would read 01:14:05.000 (by which the time format becomes obvious; I never bother about the milliseconds but just then delete unwanted frames afterwards). (I identify the wanted number by number of wanted seconds multiplied by 25, then plus some.)
Now for the %04d part: 2,000 frames is 4-digits, ffmpeg will number the created picture files from 0000 to 9999; for just some seconds, that code part would be %03d, other naming conventions are available. Since you invariably need some unwanted frames at start as a safety buffer, unfortunately, your not-deleted frames will then not begin with number "1", but perhaps some "0425", so maniacs like myself then need to apply some renaming routines ("delete leading zeroes", then "name in number format minus 424" here).
Have got a 13-year-old son who's dreaming of / "preparing" the Centro sperimentale di cinematografia or the counterpart in your country? Ask him if he already applies this (or have him even explain the details to you), but for your preteen daughter, too, I could imagine wonderful use-cases* of both the full workflow, and of just the copying of some minutes of DVD by WR into some hdd format: happy sharing with them! Between blunt consumerism and Creation with the big C, there are intermediate areas worthwhile exploring, for young people and for the rest of us.
*: the very, very best moments of Justin Bieber, or then, even into adult age, dance/ballet scenes (for example) - ok, professionals know what's at their disposal nowadays, but your little girl may not know yet, so tell her!