As I said, it's quite easy to *use* a layered image in a dialog or scene, once the layered image has been correctly defined. The difficulty is to define the image so that it can be used. If not done properly, you end up with a girl having no face or no arms in the best case, or a Ren'Py exception in the worst, depending on what she is to wear, what time it is, or if she is pregnant or not.
To make it worse, the layered image has a context, i.e. it depends on what other image has been shown in the same scene before. A very simple example would be (something like that really is in the game):
Code:
show diane b_magic f_happy a_hips
which would show Diane, being happy, with her arms on her hips. But that is supposed to work regardless of what she wears (naked, cow outfit, overall, dress...), if she sits or stands, if she is pregnant or not, or even if she is covered in some body fluids or not, not to mention if she is currently being silent or talking. To make it work, it has to be put some effort in *defining* that image in the first place, after all the assets are being drawn by DC. Therefore, the naming of her body "b_magic" is not an exaggeration at all
I hope you are refering to old assets (before introduction of the layered images). If he now starts to rename everything after the Jenny update, that would be the end of it...