After you've download the free Photoshop Mix app, open it on your device.
Tap the + to create a new project. Choose an image of your campus that you captured with your device camera.
In the project window, tap + to add a second image like a spaceship on top of your background image.
Optional: If you want to re-create the composite in this tutorial, you can purchase the spaceship and campus photos from Adobe Stock. You can then open them in Photoshop Mix by tapping +. See Adobe Stock and CC Libraries for more information.
Tap Cut Out, then Subtract. Drag your finger over the parts of the image you want to remove. In this case, drag over the sky to separate the spaceship from its background.
The edges of the cut-out are refined automatically, but you can experiment with other Cut Out options to make further edits. Tap the Checkmark when you're happy with the cut out.
Use pinch gestures to reposition and scale the spaceship layer to fit more naturally into the background scene.
Tap the Share icon in the menu bar, then Send to Photoshop. A short time later, a layered document will open in Photoshop on your desktop.
Tip: If you don't see your composite in Photoshop, make sure you're signed into your Creative Cloud account.
In Photoshop, select the Mask Layer in the Layers panel. Select the brush tool and open the brush properties control at the top of the screen. Set Hardness to 5%. Then set the foreground color to black.
Working in smooth motions, paint onto the mask to hide any hard edges. In this case, paint over the edges of the dirt surrounding the spaceship. This will help make a convincing blend between the two photos.
Click the New Layer icon to create a new blank layer for the shadow beneath the Spaceship layer. Rename your new layer Shadow.
Use the Lasso tool to draw out a selection in the shape of the shadow.
On the new layer select the Paint Bucket tool (Gradient Tool > Paint Bucket Tool). Then click to fill the selection area with black.
Use the Opacity slider in the Layers panel to reduce the opacity of the shadow to 50%.
Save your image as a JPEG (File > Save As) so you can share it with your friends on Facebook or Instagram.