Hey there @kryro4! Welcome to the community! Some of your key mechanics seem to be best done using Render Targets (older documentation) and Scene Captures. For your camera function pseudocode would be to trigger a scene capture 2d attached to the camera to take a picture, then apply that to a render target material and put it on an object or the UI for the player to view. You may want to export the render target as a PNG if players intend to keep each image, but if not you can then just apply these materials to decals or actual photo meshes and move them around on the scrapbook later.
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