Google's Device Art Generator is certainly not used by the same number of users of Android devices, but it does serve the very useful purpose of putting an app screenshot or artwork onto the display of device artwork. If you're a developer or a user who wants to place the screenshot of an app onto a device to show what it might look like Device Art Generator is the tool you would use for this purpose. Not long after their official launch the Pixel and Pixel XL are now included in this tool alongside an Android Wear smartwatch, the Nexus 5X, and the Nexus 6P.
The timing of this addition is a little bit later than it was last year when Google added the two new Nexus phones, having done so in the beginning of October of last year, but it's also possible that the addition of the Pixel and Pixel XL happened later because the devices also launched later. The devices in the image below are the only ones you'll see right off the bat, but the Device Art Generator does still include the Nexus 9 and the Nexus 6 artwork as well, which can be viewed by simply clicking on the little arrow next to the "older devices label."
While this tool is mainly meant for developers, really anyone can use it as it isn't required to have a developer account to reach this page. An average user get to it simply by heading to the Android Developers webpage, or just by clicking on the source link below which leads right to it. In regards to the tool, it's also super simple to use and Google lays out the instructions in two steps, which include dragging a PNG image on top of the device artwork, after which the Device Art Generator will do just as the name suggests - provide you with artwork that has the screenshot shown on the display. Of course, this won't happen before you have the chance to customize it, but once that's all said and done you can then drag the final result of the device art that the tool has generated for you, complete with a fresh screenshot, to your desktop and use it as you please. It is worth noting that the PNG image file used has to be of a certain aspect ratio. More specifically an aspect ratio which matches that of the device you're dragging the image to.