What it means to draw the "touchable area"

When you stop drawing the boundary, the area fills in. You can now test tapping within the area or outside to see it working.
If you are unhappy with the area you drew, press the Draw Outline again button.
Three controls have appeared to control a Color overlay. This is a hint that will be shown on the Touchgram page for where to touch.
- You can use the switch to turn the overlay off so there's no visible hint.
- The slider lets you adjust the opacity of the hint, so more of the background shows through.
- There's a little color swatch rectangle above the slider - tapping it lets you pick a different hint color.
The hint color starts automatically generated as a contrasting color with your picture.