Use preview when adjusting filter settings

To use preview, simply click (the Preview button). This will select an area in the image and automatically apply filtration to this area. Alternatively, you can manually select any image area (press the left mouse button, drag the mouse and then release the button). When an area is selected, Neat Image will (if auto recalculate preview option is enabled; see Filtration options) automatically apply filtration to the selected image area. You can also manually update the preview using the Preview button, or the Filter | Preview menu item, or the F5 hotkey.

As soon as the preview is ready, you can left-click inside the selected image area to temporarily switch back to the original image for comparison.