I'm looking for free software to create a 5 second intro for my youtube videos. The intro video will have 2 images: image #1 is the background and image #2 will be a picture of a small item moving around with image #1 kept as the background.

Can anyone recommend a free software to do this? I would guess it shouldn't be too hard to do this but since I am completely new to this I really don't know.

thank you