test.py

from kivy.config import Config
Config.set('kivy', 'log_level', 'debug')

from kivy.app import App
from kivy.lang import Builder
from kivy.factory import Factory
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.image import Image
from kivy.properties import ObjectProperty

kv = """
#:import rand_float random.uniform


<Test>:
	image_list: image_list
	GridLayout:
		id: image_list
		size_hint_y: None
		size_hint_x: None
		width: root.width
		spacing: 20, 0
		padding: 100, 50, 0, 50
		cols: 1
		height: sum( ( x.height + 50 ) for x in self.children )
"""


class Test(BoxLayout):
	image_list = ObjectProperty( )

	def __init__(self, *args, **kwargs):
		super(Test, self).__init__(*args, **kwargs)
		self.add_images( )
		self.image_list.export_to_png( "test.png" )

	def add_images( self ):
		for i in range( 1, 5 ):
			widget = Image( source = "{:04d}.JPG".format( i ), size_hint = ( None, None ), size = ( 2000, 500 ) )
			self.image_list.add_widget( widget )

class TestApp(App):
	def build(self):
		return Test()


if __name__ == '__main__':
	Builder.load_string(kv)
	TestApp().run()