In art packages you can set up a set of instructions in a small text file (or script) that uses the packages' built in functions to perform a set of automated actions on an image (resize, add borders, add effects etc.)
A plug-in is like a deluxe script but while a script uses the functions Photoshop (or whatever package is being used) has as standard, a plug in adds
new functions.
Scripts can be found in the
'File' menu ..
.. you have to download and install them first though obviously .. there are loads of scripts out there and a lot of them are free.
Plug-ins are installed like a stand alone program and add new functions to the
'Filter' menu ..
.. starting these usually opens up a dialog box allowing you to alter how the plug-in works without having to tinker with the code direct ..
.. these are all over the shop, availability wise, with a fair few free ones but the more useful ones usually come on a 'purchase only' or 'shareware' standing. But as we all know - there are ways and means to save loads of money when it comes to this sort of thing.
I like him ... He says "Okie Dokie!"