Express Border uses Monochrome Threshold to separate shapes from the background. This leaves black shapes on a white background. Any solid or fully enclosed shapes in the picture will then have a border added around them. If there are shapes within shapes, the inner shapes will be ignored.
Pictures with Dark Borders and Backgrounds
A picture that has a black or very dark border or background may simply create a rectangular border. This is especially the case if the background or border cannot be removed with Monochrome Threshold.
For pictures with a dark border, it may be possible to remove the border on the Rotate and Crop Picture page of the ExpressDesign Wizard. If this is not possible, edit the picture to remove the border or change the border color.
For pictures on a dark background, use a picture editor to invert the colors in the picture or change the background color to a light color.
After editing the picture, load it again in the ExpressDesign Wizard.