When it comes to applications that use many images, it is important to reduce their loading time, especially when they are requested from a remote server.
Note
One strategy to reduce the loading time is using an Atlas (also known as sprites). This reduces loading time because all the images are packed into one image, so it only needs to be requested once.
Here is the atlas image we use for the Invaders Revenge:
Instead of requesting five images for Invaders Revenge, we will just request the atlas image. We are also going to need a json file that tells us the exact coordinates of each image. The good news is that we don't need to do this manually. Kivy provides a simple command to create both the atlas image and the json file. Assuming that all the images are in a directory called img, we just need to open a terminal, go to the img directory and run the following command in the terminal:
python -m kivy.atlas invasion 100 *.png