Very well, just minor editing necessary.
1) Upload a pic, address at @altbot as "private"
2) wait for the reply (might take quite some time), edit
3) Generate the post, using the reply
OR
1) right your post as usual, type cc @altbot
add [#AltText will be added]
2) Upload and wait
3) return to you post copying the bots suggested text
4) delete the @altbot references (or their might be awkward messages to the people replying in the convoy)