There is no simple built-in command to center a window on a Mac. But you can use other techniques. Learn how to combine two window movements to center a window, or use scripted Shortcuts, or a third party app.
Learn more about creating your own Shortcuts by following along with this watermark tutorial. Build a Shortcut that will add an overlay to an image file and save the file to the same location with a new name. This can be the basis for all sorts of image modification Shortcuts.
You can create a Shortcut that will allow you to capture a portion of your screen, and then the text from that image will be extracted and placed in the clipboard. This is useful where you can't normally select and copy text from websites and apps.
Learn how to create a Shortcut on your iPhone that you can activate with your voice to turn on Do Not Disturb. The Shortcut will then ask you for a number of miniutes and automatically turn off. You can also set it to activate silently as a Home screen icon.
You can use the Shortcuts app on your iPhone or iPad to create a quick method to shrink an image before sharing it. With this more advanced Shortcut, you can choose a size in pixels or percent, and select the image format and quality.