file 'file_000.png'
file 'file_001.png'
...

ffmpeg.exe -framerate 5 -y -f concat -safe 0 -i list_of_file_names.txt.txt -c copy output.mp4

file 'file_000.png'
duration 0.2
file 'file_001.png'
duration 0.2
...
file 'file_099.png'
duration 0.2
file 'file_099.png'

.ffmpeg.exe -safe 0 -y -f concat -i .list_of_file_names.txt -r 5 output.mp4