This puzzle seems to have irregular additions in the form of pictures.
The arrows are strange additions too.
To make a bar empty, act like children. Don't forget to apply that final arrow to reach the answer.
BAR is to BARREN as CHILD is to CHILDREN. Now what does that ox have to say about the plural of ALBUM? The right-pointing arrow wants you to apply the trick to the 10-letter message you'll find... the 11th letter reinforces the theme as well as giving the answer's first letter.