In my previous Article I have generated many similar images with the scripts.
Now I create a folder and I put all my images that I need to remove the background
To remove the background you need an extension https://github.com/AUTOMATIC1111/stable-diffusion-webui-rembg.git , you can add in the extension tab "Install from Url"
In the Extras tab you can clic on "Batch from Directory", set the folder with your images and another folder where you wanna save the results.
In the bottom you will have the new extension "Remove Background", there are different options, u2net works well. (You can try also the others).
Press Generate and you will get your images without the background.
I can now use a video editor, I will use Kdenlive (https://kdenlive.org/it/) , a free video editor.
I import the images without background and I set a background in another layer.
of you can generate an animation with transparent color with screentogif (https://www.screentogif.com/)