Make sure you have installed GIMP on your PC. Launch the app and open the input image. Click on Blur/Sharpen Tool. Set Convolve Type to Sharpen. Customize brush settings. Set sharpen rate ...

You can also open the image in GIMP by opening GIMP and then creating a new canvas by going to File then New to open up the New image dialogue box. Choose the settings that you want for your new ...