Step 1:
Paste an image on your canvas.

Step 2:
Click on the picture. Then click on Filters>Others>Find Edges.
The imageshould be darkened with the lines highlighted.

Step 3:
Go to the Properties below the screen and click on Blend Mode and pick Difference.

Step 4:
Click on Filters>Sharpen>Sharpen.
The lines will show up a little darker

This is my final image