To export a screen to PNG use the Export to Image action. This action can be invoked from the Toolbar, Context Menu or just by pressing Ctrl+Shift+I shortcut.
The exported image can be saved to clipboard or to a file. It’s also possible to export current selection only by choosing Selection only option which becomes available when something is selected in the editor.
You can also choose a scale to export a smaller or larger image than the actual size.
Next: Exporting to PDF