Not sure what makes you believe storing an image path is any different from storing other information in JSON. I’d argue there is no such thing is a json pro": it’s a way of writing down text-based information in a structured way, nothing advanced.
var data = {}
func save_game():
data["image_path"] = $Sprite.texture.resource_path
var file = File.new()
var error = file.open("user://savegame.json", File.WRITE)
if error == OK:
file.store_line(to_json(data))
file.close()
func load_game():
var file = File.new()
var error = file.open("user://savegame.json", File.READ)
if error == OK:
data = parse_json(file.get_line())
file.close()
$Sprite.texture = load(data["image_path"])
perhaps he wants to store the image itself in the json, encoding to base64 or something?