With macOS Mojave, Apple lost Grab, the screenshot app that is lived Applications gt; utilities because dinosaurs roamed the earth and replaced it with a program that was simply called Screenshot. You may have noticed that use Command-Shift-3 or Command + Shift + 4 to take a screenshot with Mojave, you show a small thumbnail of your image in the bottom right corner of your screen.
If you ignore the thumbnail, it will end after a few seconds where your default location for the screenshot is located (usually the desktop). If you click on it before it disappears, you'll get a markup toolbar so you can add embellishments, and your Mac saves the changes when you click "Done".
I know I often say this, but if you do not like this change, you can turn it off, so your screenshots behave like they did under High Sierra. (But you still have access to the nice new Screenshot app yourself if you want to use it.) All you have to do is: Open screenshot from Applications gt; utilities or by clicking on the icon in your Dock …
… or use the corresponding shortcut, namely Command-Shift-5. No matter how you enter, you will see a new screen graphics interface with a bar at the bottom; if you click on "Options", there is the "Show Floating Thumbnail" preference, which you can click to disable.
As you can see, you can also use these options to save screenshots to a different location, enable a timer so that you can set a scene before the photo is taken, and so on. And the square icons on the left of that bar let you choose between capturing windows, capturing the entire screen or even recording the screen. But by disabling the "Show floating thumbnail" option, you can go back to High Sierra, at least as far as your screenshots are concerned.
Finally, here's another quick trick: if you're quick and right on Check – click on the thumbnail after you've taken a screenshot, the contextual menu you open will give shortcuts to put the item right into Mail, for exle or for save in documents instead of on your desktop.
OK, that's pretty cool. I admit that I have restored Grab from my Time Machine backup, just because I like it, but this little feature can cause me to use Screenshot … and even let that floating thumbnail turned on. Maybe I'm not that old fart who is afraid of change.
No, I'm completely.