There is example scripts there on how to use Image Events.
Otherwise there are numerous other tools. As to attaching the scaling to a folder action there are a number of related threads for folder actions on this board:
IMPORTANT: the file formats supported by Image Events for read access are: PICT, Photoshop, BMP, QuickTime Image, GIF, JPEG, MacPaint, JPEG2, SGI, PSD, TGA, Text, PDF, PNG, and TIFF. All of these formats are not supported for writing or saving.
?? What do they mean with this? I cant scale the JPG’s? :?