KIvy AsyncImage and cache

[Klieber frederic]

Consider this simple example:

# coding: utf-8

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.lang import Builder

Builder.load_string('''
<Widget1>:
    id:wi
    btn:btn
    BoxLayout:
        orientation:'vertical'
        btn:btn
        im:im
        pos: self.parent.pos
        size: self.parent.size
        AsyncImage:
            id:im
            source : 'http://lorempixel.com/400/200/'
            size_hint_x : 1
            size_hint_y: 1
            no_cache:False
        Button:
            id :btn
            text:'Click me !'
            size_hint_x : 1
            size_hint_y: None
            height:50
            on_release: wi.click()
''')


class Widget1(Widget):
    def __init__(self):
        super(Widget1, self).__init__()

    def click(self):
        # HERE IS THE PROBLEM : ......
        self.ids.im._coreimage.remove_from_cache()
        self.ids.im._coreimage.source = 'http://lorempixel.com/400/200/'


class WindowApp(App):
    def build(self):
        return Widget1()


if __name__ == '__main__':
    WindowApp().run()

The page 'http://lorempixel.com/400/200/' returns me another picture each time I'm refreshing the page in a browser.

I'm trying to mimic the same thing in Kivy BUT without using no_cache:True in the kv.

The "remove_from_cache()" does not work in this case, but I'm probably doing something wrong.The picture is  updating after some period. corresponding to kivy's setup, but this is not what I want.

The situation is I'm retrieving 100's of covers with the REST API from my MediaCenter software and replacing- sometimes- some of them retrived from the Web.

I do not want to load all the covers each time when I'm browsing in my Kivy app., but I would be able to "reload/reset" IMMEDIATELY the ones who have changed but still at the same address.

Of course, I've tried the reload() function also, but no luck.

Thanks