Здесь можно прочитать про текст в RenPy.
Цитата
Image
The image tag is a self-closing tag that inserts an image into the text. The image should be the height of a single line of text. The argument should be either the image filename, or the name of an image defined with the image statement.
g "Good to see you! {image=heart.png}"
Думаю там гифку ставят или настроенную анимацию, не проверял.