This ability gives the person the power to assume any shape he has memorized for the purpose.
Limits
The person cannot alter the memorized shape once she has memorized it, nor can a shape be memorized off of a drawing or other artwork - it must be a photograph either physical or digital of high resolution.
This ability requires the Perfect Memorization ability or an eidetic memory.
Types of Memorization
There are different ways to memorize a form with enough detail to replicate it.
Physical Contact / Proximity
The best way to memorize the shape of another person is, by being around that person long enough and making the effort. This process takes a considerably longer time than doing it from a photo, unless the person has intimate knowledge of the person he wishes to shift into.
If she has complete access to the other person, including without clothes, for several hours she can memorize her targets form within 2-3 hours of contact.
Sculptures / Artwork
While most of the time sculptures and artwork cannot be used for memorization, it is possible to use them to assist in the process. An accurate physical representation of a person can be used to better understand and thus better know the target, but it must be extremely accurate and free of artistic license.
Additionally, it cannot be used alone as a source of memorization unless the sculpture or painting is absolutely perfect in every detail to the real person, including aspects of skin tone, color, and texture.
Photos
Photographs can be used as a source for memorization. The process takes about 5-7 hours to complete and accurate, high resolution, photos of the target are required. Photos must be obtained of more than just the face, but the entire body. Shots of the entire body at once, close-ups of arms, legs, face, neck, etc.. Are all required. The more photos, the less time it takes to construct a proper memorized image to shift into.
Combinations
Combinations of these methods can also be used, a few hours spent with the actual person can be mixed with detailed photographs of the person and result in an accurate image for shifting.
Movement / Mannerisms
While a memorized image can be used to shift into that form, she cannot mimic the movement and mannerisms of the target unless she has training in doing so.