Gimp record actions

Solution 1:

There are two things you could try. The first is GIMP scripting or GIMP BATCH. These are ways of running GIMP in BATCH mode and scripting actions to be performed on a set of images.

The second way, which is much easier and, in your case, probably sufficient is the wonderful ImageMagick suite. You can probably do everything you want using the convert tool of that suite. The following are some relevant options, you can see the whole list using man convert or by visiting this page.

NAME
      convert - convert between image formats as well as resize an image, blur, 
      crop, despeckle, dither, draw on, flip, join, re-sample, and much more.

SYNOPSIS
       convert [input-option] input-file [output-option] output-file

-background color    background color
-crop geometry       cut out a rectangular region of the image
-trim                trim image edges
-size geometry       width and height of image