Duplicate animation images

I'm using the projects to render an effect on a number of images.

STEPS USED
1. I create a project.
2. Add a artboard. Pick a filter for the artboard.
3. Change the properties on artboard as follows.
"Background source" I use external video or sequence. Browse to folder and select the first image. (They are all named with a 1,2,3,4,5... afterwords.)
"Animation" is set to automatic.
"Settings" is set to default settings.
4. The select "render animation" under file menu. I select all frames, final quality and channel as default.
Output file(s) is set for image sequence, browsed to NEW location for output.
5. Then I hit RENDER.

I get the same effect applied to the FIRST image 5 times. It only does the first.

What am I missing?

Also I'm on a Mac and don't have the function "Use relative paths to external video or sequence". Could that be a problem?

Great thanks-I'll give that a go.