I have an audio file and I have 15 images. I would like to make a video from these 15 still images. Each image may appear for different number of seconds.
E.g. Image 1,2,3 will take 3 seconds each but image 4 may take 40 seconds because it is more complex.

How can I use ffmpeg to specify timestamp for each image and add audio to the same.

Also note that the sum of timestamps of all images = running time of the audio.

I looked at this question and image2 filter option from the official documentation but no luck in producing such a video