The significance of details in a picture is dependent on the overall size of the picture after it is cropped. Cropping the picture may bring out the required detail, as may increasing the size of the embroidery.
Even so, very small details in a picture may sometimes be ignored. To enhance these details, select Enhance Detail in the PhotoStitch Embroidery Options page of the PhotoStitch Wizard.
The effect of Enhance Detail varies with each picture, and it is always off by default.