ffmpeg : how to i set the images sequence to be equal to the duration of the movie with

Question

hello all i converted sequence of images to movie with this command :

ffmpeg -f image2 -i %04d.jpg -r 12   finale1.avi

then in the secound command i attached mp3 sound file to the created movie with this command

ffmpeg  -ab 128k -ac 2 -acodec copy -i Afterwards.mp3 -i finale1.avi finale1_sound.avi

now im facing problem that ths sequence of images are changing very fast ( like 3 seconds ) and until the rest of the movie clip i see only the last image the length of the movie is as the length of the mp3 file it is fine but i like to see the images in equle time .
example:
if i have 4 images and the length of the movie 60 sec so i want that each image will be shown 60/4 seconds.