ffmpeg mp3 to mp4 with image compatible with iphone

I need to convert an mp3 to mp4 with image using ffmpeg from my OSX command line.

I already installed last version of ffmpeg (3.0.2), and tried the following command as described here

./ffmpeg -loop 1 -i test.jpg -i test.mp3 -c:a copy -c:v libx264 -shortest test.mp4

but the result mp4 file is not compatible with my iphone 5

Now this is what I am trying

./ffmpeg -loop 1 -i test.png -i test.mp3 -profile:v baseline -level 3.0 test.mp4

but I get the error

Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height