I’ve noticed lately that when I view website images on my iPhone 4S that they look really fuzzy. MailChimp has been harping on HD graphics for emails that will be read on SmartPhone and mobile devices.
72dpi for images in emails and on websites just won’t cut it anymore … I’ve been using 250dpi lately to compensate for HD images.
I just read this blog post by the father of website useability, Jakob Nielsen. While he’s talking about fonts … he does give the dpi for all of the latest mobile equipment. http://www.useit.com/alertbox/web-typography.html