ffmpeg add a intro photo before video
Use the concat filter to join the image to the video:

ffmpeg -framerate 25 -loop 1 -t 5 -i image.png -t 5 -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 -i video.mp4 -filter_complex "[2:v]drawtext=text='foo'[main];[0][1][main][2:a]concat=n=2:v=1:a=1[v][a]" -map "[v]" -map "[a]" output.mp4



The image should be the same width and height of the video, so you may have to add the scale, scale2ref, crop, and/or pad filters before concatenation.
If the main video has audio then the image needs have audio as well. Generating silent audio with anullsrc as shown in the example can suffice. Make sure to match the channel layout and sample rate of the main input.