I've been suffering from the tedious process of re-sizing my images to convert the 3+MB image to 300+KB image!
I've googled how to do so using GIMP, & it's pretty easy. Just download DBP Plugin. DBP is a simple batch processing plugin for the Gimp - it allows the user to automatically perform operations (such as resize) on a collection of image files.
Since I'm in a Windows environment, I'v just downloaded and unzip the file, and copy dbp.exe into the plugins folder.
The batch editing window is really easy. Navigate to it from the Filters menu in the main Gimp window, select Batch Process... to bring up the DBP window. The processing steps are laid out on a series of pages, one for each step.
I liked that!! :)