This tutorial explains how to manually create a new font from images.
You need to change stroke color to something other than grey and this is how that's done:
Open the overview tab and double click on the glyph you want to edit.
The next step is to use the drawing tools to outline your background image. Select the Beziér tool and set it to use Quadratic control points (or Cubic control points if you think it makes drawing easier). Control point type:
Add new control points to your glyph. Use as few points as possible, you can easily add new control points with the tool for moving points later on.
Select the tool for moving control points. (m) You will use this tool to help you outline your background image. First, select all the nodes (points) in between the corner nodes you made with the bezier tool. As you select these points, shift+click. The color of the selected points will change to the stroke color you changed in the first four steps.
Select all the nodes in between the corner nodes. (Shift + Click)
Adjust the position of all control points and handles. You can add the points to the path by double clicking in the path. Delete points with the delete or backspace keys (break the path with shift + delete). Click on a handle and hold down the shift key if you want to keep the angle of a handle while you are changing the length of the handle. Press w to toggle between smooth node and corner node. Hold down the space key and click to move the canvas. Click on a point and press shift to move the point independent of its handle.
Open the kerning tab. Menu → Spacing and Kerning (Ctrl+K or Command + K)
Here is the image: