Automation for Batch-Converting Images for Ecomm - must have square canvas - Ug

First time here and hope this is a good place to ask.

Looking for a quick way/automation to convert multiple print quality images (30-70MB) to 1000×1000 pixels at 300 dpi and under 3 MB for use in web applications.

WHAT I WANT TO HAPPEN
Open the file (that already has image and is named with correct UPC) hit the magical automate function that automatically puts the image in those constraints first mentioned… Has anyone created a script or an action or have any other idea?

Thank you in advance!