[kia345]

Paint.NET wins.

Step 1: Open the image
Step 2: select the "Move selected pixels" tool
Step 2.5: turn the quality to "pixelated"
Step 3: Right click the image.
Step 4: Drag to 45 degrees.
Step 5: Redraw the few distortions

You could also highlight the image sprite rather doing the entire image, that's usually easier.