Problems

Welcome to Apple Support Communities btarmory,

Sounds like your MacBook Air is running slowly, is that right? Do you only notice this when you screenshot something? Since noticing this, have you restarted your Mac? You can also confirm there are no updates available for the macOS ( latest is macOS 11.5.2) or any applications.

Log out, sleep, wake, restart, or shut down your Mac

Update macOS on Mac

You can also try the troubleshooting steps in this article: If your Mac runs slowly.

Have a good one!

btarmory,

A 1 to 2 second delay for the preview of your screenshot to appear, sounds like expected behavior. You can submit feedback directly to Apple if this concerns you here: Product Feedback.

Take Care!