Have you ever looked at various blogs (such as this one), designers, or company websites that show off their app or website with a slick looking, professional looking render of an iPhone or Macbook? Perhaps you want to have the same nice looking presentation for your own app, but don't want to muck around in Photoshop, take the photo yourself, or pay tons of money for a premium service.
I found myself in this situation a while back, and through some research found a variety of great tools that can help you achieve just that. I've compiled them in this post for anyone who may find themselves wanting great product shots on the fly.
My favorite - Dunnnk
My personal favorite way to generate product shots of my apps is a great web service called Dunnnk. Dunnnk is incredibly slick and simple to use, as well as generates super high res (2k) mockups - all for free. They have a variety of images in different categories, such iPhone, Android, Mac, Apple Watch, and more. All they ask in return is that you subscribe to their newsletter, presented completely unobtrusively at the top of the page. My only gripe with this service is that for my needs, the templates get old - as the selection is somewhat small (though high quality) and similar in style between images.
Go for variety - Smartmockups
When Dunnnk doesn't have the exact type of image I am going for, I tend to try Smartmockups instead. Smartmockups has a great variety in terms of templates, from the traditional "phone holding iPhone" to more creative ones with iPhones on tables, in cars, and other great looking backdrops. Smartmockups works very similarly to Dunnnk, in which you simply upload your image and get the mockup. One nice touch is that you are able to select the size of the final image you want, so if you don't need obscenely high res images, you can do their servers a solid and bump the size down.
Just the frame - Mockuphone
In the event that you don't want the fancy looking backdrops provided by Dunnnk and Smartmockups and instead just want to put your screenshot on an iPhone frame, Mockuphone has you covered. Provided by the makers of the amazing MakeAppIcon, Mockuphone is a simple service that allows you to select from a limited set of iPhone frames, upload your screenshot, and get an image of your app on an iPhone. Simple as that. The images are high-resolution PNG images with transparent backgrounds, which makes them pretty flexible to use.