Batch convert multiple PDF to Image on Mac

Automator has a "Render PDF Pages to Images" action. Under Snow Leopard and El Capitan, there's a wizard that pops up when you run Automator asking you to choose a template. The second template is "Application":

Applications are self-running workflows. Any files or folders dropped onto an Application will be used as input to the workflow.

So:

• Open Automator
• Choose "Application"
• Drag the "Render PDF Pages to Images" action onto the workflow
• This action produces random filenames, so follow it with "Rename Finder Items" (choose "Make sequential" from the dropdown list(you can skip this action in Sierra as it no longer exists and it just uses original file name)
• Then add a "Move Finder Items" to have the output files moved to the Desktop (You can click on the "desktop" and choose a different location for the output files to go)
• Save your new application somewhere (I suggest saving to the desktop makes it easy for drag and drop)
• Drag files onto it
• Enjoy.