I love illusions, including Silent Image, but unfortunately I don't think it's always handled correctly. I'd like to clarify the RAW interpretation of this spell for this purpose.
Here is the text of the spell:
Silent Image, 1st-level illusion
Casting Time: 1 action, Range: 60 feet
Duration: Concentration, 10 minutes
... The image appears at a spot within range and lasts for the duration. ...
You can use your action to cause the image to move to any spot within range. ...
When Silent Image is cast, does it move normally on the round you cast it, and continue to move if you use your action to move it on the next round? Or is it a still image on the first round, and you can only make it move normally on the next round?