Deforminator_PIL is a matlab graphical user interface for deformable linear registration of MRI images, and was developed for use in lung MRI. The algorithm performs Projective image registration, using a GUI interface in matlab, using the outline of the lung as the constraints. The technique assumes all images were acquired close to a target volume, typically Functional Residual Capacity (FRC) and that no large deviations in lung volume are present in the dataset. The technique will produce unreliable results for variations in lung volume >10-12% above or below target volume. The original algorithm and interface was developed by Tatsuya Arai in early 2014, and has undergone a few revisions since its first incarnation. Rui Carlos Sá added a "wrapper", shared it using github and added a few add-ons in March 2014; Amran Asadi significantly improved usability of the GUI and produced a compiled version that only requires the free Matlab runtime environment (not full Matlab). v1.0.1 adds LoadAllDicomFiles for a complete, self contained release. The code assumes data/images exported are files containing "MRDC", followed by the image number; compatibility with other scanners is not built in, but can be added by changing a single line in the Deforminator_PIL main function (see "Issues" tab). v1.0.2 Crippling typo in LoadAllDicomFiles, introduced with v1.0.1 was corrected. v1.0.3 Two different versions of LoadAllDicomFiles were erroneously distributed - fixed.