Motion track image does't appear in render

Question

I make sure the transparent checkbox was hit, but the only thing it appears in render is this.

Answer 1

The images used in the workspace are for reference only.

Go to compositing workspace, check Use Nodes and thenShift + A > Image Sequence.

Then Shift + A > Viewer and connect image sequence to the viewer and Composior node. If the image size doesn't fit, you can try to use Scale node, I am not that sure if that's the right name

The basic node setup for tracking is described here:

Transparent rendered object over tracked background