In macOS, you have easy way to take screenshot. You can shortcuts to capture screenshots of entire screen or selected part of the screen. All these screenshots are saved on the desktop in .PNG file format. If you want to change the image format, there is no straightforward option for this. If you still want to change this, you can do this using the steps given in this article.
You can change the default screenshot image format to JPEG, GIF, TIFF, and PDF. Here is how to do this.
Change macOS Screenshot File Format
Launch Terminal. You can do this by clicking on magnify icon at the top right side of the screen, type in “Terminal” and hit Enter.
In terminal, you need to use the following command.
defaults write com.apple.screencapture type jpg;killall SystemUIServer
After this comment, all screenshots will be saved in the JPG file format. For other file formats, use the commands given below.
defaults write com.apple.screencapture type gif;killall SystemUIServer
defaults write com.apple.screencapture type pdf;killall SystemUIServer
defaults write com.apple.screencapture type tiff;killall SystemUIServer
You just need to change the type thing in the command. You can always go back and change the default file format to .PNG. Just use the type png in the command.
Now you know how to change the default image format for screenshots. If you prefer any specific image type, you can use tip given in this article to change it.
If you have anything specific to ask, you can always leave a comment.