Actions selection action help

[bacarozzo]

i have to do an action that automatically make a selection of the picture.

the selection is a rectangular in the bottom of the image like this:


the problem is that the size of the image in not always the same.
how it possible to make a selection relative to image size?

any help, link, or guide are appreciated

 

[bacarozzo]

found solution,
select all -> select transform selection -> in the upper left corner select the bottom point -> give a % in the H: (14%)
now i have tehe selection within the bottom of the image so
select transform selection -> in the upper corner select the upper point -> give 50% in the H:

:-D