Run Adobe Photoshop or alternative photo-manipulation software, such as GIMP or Google Picasa, by double-clicking on the desktop icon.
Click "File," then "Open," and select the image you want to convert to a silhouette from your computer's directory.
Choose the "Free Select Tool," which is represented by a lasso symbol from the tools panel on the right-hand side of the program.
Draw around the section of the picture you want to convert to a silhouette by clicking around the section until it is all marked out by a dotted line.
Click "Subtract from Current Selection" and draw around any sections that you don't want to be converted to silhouette, for example an area created when a model has her hands on her hips.
Click "Colors," then select "Colorize" from the drop-down menu. Adjust the "Lightness" bar by moving the slider to the left-hand side to black out the selected sections of your picture.
Use the "Brush Tool," marked by a paint brush symbol, to touch up any areas of the silhouette that have not been covered properly.
Repeat the process for the remaining sections of your picture or for any other pictures that you want to convert to silhouette.