imageAlter is an Acrobat plug-in for repurposing PDF files by downsampling and recompressing the images without requiring re-distilling. In addition, imageAlter has an unique feature called "Alternate Images" which can significantly speedup Acrobat when working with large high-resolution images.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.