According this I try to put two pictures on video
ffmpeg -i video.mp4 -i photo01.jpg -i photo02.jpg -filter_complex "[0:v][1:v] overlay=25:25:enable='between(t,10,20)';[0:v][2:v] overlay=25:25:enable='between(t,25,35)'" -pix_fmt yuv420p -c:a copy output.mp4
no errors, but it shows only the first image, and the second is not show up.