This command applies the overlay image to only the first image of the slideshow series. I messed with labeling and can’t figure out the correct labels to get the overlay to apply to all images in the video.
/opt/bin/ffmpeg -y -framerate 1/3 -start_number 1 -i %01d.jpg -i $watermark.png -filter_complex "pad=500:500:(500-iw*min(500/iw\,500/ih))/2:(500-ih*min(500/iw\,500/ih))/2:color=white,overlay=250:420" out.mp4 2>&1
>Solution :
See this works:
/opt/bin/ffmpeg -y -framerate 1/3 -start_number 1 -i %01d.jpg \
-loop 1 -framerate 1/3 -i $watermark.png \
-filter_complex "pad=500:500:(500-iw*min(500/iw\,500/ih))/2:(500-ih*min(500/iw\,500/ih))/2:color=white,overlay=250:420:shortest=1" \
out.mp4 2>&1
If you want to show the same overlay image on all frames, you need to loop the overlay image. Since the looping will go forever, you need to stop with -shortest option to stop encoding when the first input ends.