Sizing images for screen and print output may be one of the most confusing and misunderstood concepts in digital photography, which is deceiving because it appears pretty basic on the surface. Even after more than a decade of moderately hardcore Photoshop use I still find new ways to confound myself in this area. This topic is steeped in misunderstanding, urban legend, faulty logic and general confusion. Screen resolution vs. print resolution? What is the correct resolution for the web? To resample or not to resample? How much can I enlarge an image for printing? Why shouldn't I upload a bunch of full resolution 21 megapixel images to Facebook or email them to grandma?
I have published an article on the Photo Cascadia Blog that I hope will help clear things up a bit and allow folks to get a firm grasp on exactly how best to size images for different purposes. However, if you are a recreational photographer who isn't concerned with optimal image output, you should maintain your blissful state of mind and avoid reading this article at all cost.
If you are already involved in using Photoshop or other photo processing applications to size your images then it could be a worthwhile read. You might be interested to know that screen images don't need to be 72 ppi (pixels per inch) and that, in fact, ppi resolution doesn't have any affect on how images appear on the screen? And what about always printing at a certain resolution such as 300 or 360 ppi? The reality is that resolutions as low as 180 ppi can produce prints that look the just as good to the eye as higher resolutions and sometimes even better. Check out the article to learn more and find out my personal guidelines and workflow tips for sizing images.