Recently, I had an app rejected from the Apple App store. The rejection was due to the use of a mobile device being depicted in one of the tutorial screens. Does anyone know of any guidelines for device imagery use in-app for iOS devices?
Apple has strict usage guidelines on depicting apple products and trademarks.
Although there are no specific guidelines for using device images in an app, the App Store review guidelines do mention the general guidelines for using apple trademarks.
From reading the relevant guidelines, as long as you use the Apple provided images and follow their usage guidelines, and the image can be seen as being used to "promote your app", it should be allowed. Otherwise, it probably isn't allowed. But, anecdotally, it seems to depend on the person doing the review, as Apple don't seem to be consistent in upholding their own rules.
Relevant documentation (with excerpts):
8. Content and Intellectual Property Rights
8.1 Apps must comply with all terms and conditions explained in the Guidelines for Using Apple Trademarks and Copyrights and the Apple Trademark List
Depictions of Apple Products
2. Compatibility: If you are a developer, you may show an image of an Apple product in your promotional/advertising materials to depict that your product is compatible with, or otherwise works with, the Apple product or technology, provided you comply with the following requirements:
2.2 Image use
The Apple product images of Apple Watch, iPad, iPhone, iPod touch, and Apple TV can be used only to promote your app available on the App Store. Feature only products for which your app is currently developed. Do not use a product image if your app is not designed to display on the screen size and resolution of that product. For example, do not feature iPhone 5s unless your app displays at 326 pixels per inch at 1136-by-640 resolution.
You're not allowed to use competitor logos, pictures of devices or any material that the company owns or is competing with. This is just Apple's policy. If Apple didn't approve you to use the picture then they will reject it. If that mobile device was an iPhone or iPad you will have to remove it. Just one of their strict policies.
Diving a little deeper from a comment. If the imagery is used inside the app or content then it is typically rejected. If the product imagery is used for the store then that, to my understanding, is allowed. Another factor to keep in mind is Apple can make errors, if you feel this is an error on their part you can question the ticket error to be reviewed.