I combine multiple audio files with FFMPEG as
ffmpeg -i 1.mp3 -i 2.mp3 -i 3.mp3 \
-filter_complex '[0:0][1:0][2:0]concat=n=3:v=0:a=1[out]' -map '[out]' out.mp4
Then, I add a still image to the created video as
ffmpeg -loop 1 -framerate 1 -i photo.jpg -i out.mp4 -tune stillimage -shortest out2.mp4
How can I add the still image to the first command to make the video in one single process?
Disclaimer: I deleted my previous question as it was unclear and asked a new one.