I do a lot of Linux scripting but Windows .BAT files are something which I haven’t touched since the old MS DOS times.

Here’s a simple .BAT file which you can use to easily convert video into a jpeg sequence using ffmpeg:

echo Converting %1 to jpeg sequence
mkdir "%~d1%~p1%~n1"
c:\work\ffmpeg\bin\ffmpeg.exe -i %1 -q:v 1 %~d1%~p1%~n1\%~n1-%%05d.jpg

You can copy this into “%userdata%\SendTo” so that you can use this by selecting a file and right clicking. It creates a sub directory into the source file directory and writes the sequence there.
Most of the magic is in the weird %~d1 variables which I found out from this StackExchange. I use this to convert my GoPro footage into more suitable jpeg sequence which I then use with DaVinci Resolve.