RTFM time... nah, this watch was used so much that the majority of its interface is still muscle-memory ;)
software... ah, software.
screenshots do nothing to convey the joy of the Windows NT4-esque teal and boxes interface.
It runs under Wine okay, but not Win10 (I had a VM handy, useful for work purposes from time to time, don't judge) at all, under any compatibility options.
Remember that serial port Casio PAD-2 infrared adaptor?
software recognises Com1-8 only. in Wine. at 115200 baud.

Regedit in Wine.
HK_LOCAL_MACHINE/Software/Wine/Ports
add a String
call it Com1
edit its value to be /dev/ttyUSB0
(or whatever yours shows up as)
Ok that, then back the hell away from Regedit sobbing quietly.
next, I feel the need, the need for speeeeeed.
make sure you have permissions over your usb to serial adaptor.
sudo chmod 777 /dev/ttyUSB0
will do at a pinch.
next up,
stty -F /dev/ttyUSB0 -a
shows you what the port is doing now.
stty -F /dev/ttyUSB0 115200
sets the speed. yay.

Run the Casio Link software again...
File -> options
set your output directory to where you can find it again (thanks Wine. your directory structure attempting to overlay that of non-Windows OSs is nothing short of random)
set your comms to port 1 and the PAD-2 adaptor
set your chosen output format (use BMP here)
Okay that stuff.
aaaaaaand...
wait, I can upload 1, upload all, but download is greyed out?
Oh. Casio made this a bit backwards in my brain.
Upload *from watch*
Download *to watch*
D'oh

that all done, set the watch to Comms -> PC, put it soooo clooooose to the infrared adaptor (like an inch or two max, and facing straight-in)
upload-all aaaaaand slowly it slurps the images down.
blimey.
it worked.
Next up, convert those pics from bmp to png (minor space saving as only 120x120 pixels anyway, but let's aim for compatible with today...)

Well bother.
I have now found my hardware keyboard to add in some ALT text for the pics in this thread, and my phone's mastodon client crashes if I edit my posts.

I will now go and cry in accessibility.
...and see if I can edit them on my laptop instead.

A quick meetup with someone else from here doing a random project and we have a few more pixels to share...

@matsimpsk it was amazing at the time. digital photography in 2000 was odd, and this was a pretty good attempt by Casio to remain relevant.
full geekery-meets-007 points for the time, and it talking to everything else via irda was amazing.
I'm waiting on a replacement 18mm watchstrap to land (original is a bit stiff now, not too comfy, and I suspect will start to crack with any use).
then the comedy starts.
from previous use - it thrives on light and contrast, and everything is in focus.

@evilstevie yeah, I remember using a QuickTake 100 way back in the day. They were super expensive and the quality was terrible, but something about them was magic https://en.m.wikipedia.org/wiki/Apple_QuickTake

@matsimpsk it was the immediacy vs film cameras at the time.
you could see in near-realtime what the result was, and it was amazing.

I waited until Sony brought out their first dslr to learn photography properly because I tend to learn by brute-forcing and this made the feedback loop into seconds-for-hundreds-of-photos rather than the film week-for-36-photos and trying to remember what changes I'd made between shots.
serious respect to any self-taught photographers in the film days.