Welcome to the forum.
Getting started with the Glowforge can seem overwhelming at first, but you are going to get the hang of this pretty soon.
A screenshot is an image, a photo, and is not seen as something to cut by the Glowforge. Images are engraved and vector lines are cuts or scores. Here is some information regarding how the Glowforge “sees” pictures and lines: Glowforge Interface - Vector Files Made Easy 🤔
I suggest becoming familiar with the interface by working through some tutorials and learning about vector and raster files. You will be making earings soon.