GUIDE: Export method for top quality web images.
At the Pennywise most our graphics department uses inDesign for most image production. In the past, we would open the final pdf, then convert them to a jpeg for the web using Preview or Adobe Acrobat. I was always finding the images to come out with terrible artifacts and choppy lines.
The best practice is to open the original inDesign file, and simply export it as a jpeg with maximum quality, progressive baseline, 300ppi, and (because this is for the web,) RGB colour space.