Portraits animations are a very promising way to enliven all types of lines and replace missing portraits. Too bad default renpy animation functions don't support half of their methods...
What about yzoom and anchors?
block:
linear 1 yzoom 1.1 anchor (0.5, 1)
pause 0.1
linear 1 yzoom 0.9 anchor (0.5, 1)
repeat
The top edge remains in place while the bottom goes up and down thanks to repeat. While I need the bottom edge to remain in place and the top one to move up and down.
Again, this sh*t ignores anchors, I tried them everywhere I could, even inside linear itself