Being able to use Set-LiquitSetting powershell command to set an Image

In a migration scenario I would be able to get an image (background for example) using a powershell command, but I'm not able to set the image I got using Set-LiquitSetting.

Following error is shown:

Set-LiquitSetting : Failed to convert value for property named 'value': Unable to cast object of type 'Liquit.Rest.RestCustomEntry' to type 'Liquit.Server.BLL.Content'.