There are a variety of web and desktop application tools that allow you to edit, manipulate and create artwork from your digital photographs. Some of these programs perform simple functions such as touchups, airbrushing and colour conversion, while others offer more advanced options. One interesting way to use your digital photographs is to convert them into line drawings. Line drawings come in the form of vector files, which you can recolor and resize any way you want to create a completely new look and effect for your photos.
Use a free online line-art converter such as Vector Magic. This program allows you to upload your photograph, convert it into a traced vector format, view it and then save it to your hard drive in a number of common file formats. Before saving, you are also allowed to make some custom adjustments to your line art drawing as well, such as included colour ranges, detail levels and background edits. Vector Magic also gives you the option of sending your more intricate photographic compositions to them for a fee. Vector Magic will produce a hand tracing, which will produce the most detailed and accurate line-art version of your photo.
Download the trial versions of raster-to-vector conversion programs such as Photo to Cartoon or Auto Vector, both of which allow you to open your digital photograph files and convert them to vector line-art files. Like Vector Magic, you can customise the amount of detail you want to retain, the smoothness of the vector lines and the colours that are retained and used. These programs also allow you to resize your line art, which is a useful feature because vector line art can be scaled up or down without sacrificing image quality.
Download a free trial version of a vector program with a tracing function such as Adobe Illustrator. Using Illustrator's "Live Trace" interface, you can import any photograph into the program and almost instantly convert it into a vector line drawing. This program also allows you to customise the colours that are used and the amount of detail taken into consideration during the conversion and to manipulate or edit the lines freely upon conversion. This allows you the highest degree of control over your final line drawing.