The paper presents GALFIT, a two-dimensional (2-D) fitting algorithm designed to extract structural components from galaxy images, particularly for spatially well-resolved, nearby galaxies observed with the Hubble Space Telescope. The algorithm improves upon previous techniques by allowing simultaneous fitting with an arbitrary number of components and optimizing computation speed for large galaxy images. It uses 2-D models such as the "Nuker" law, Sérsic (de Vaucouleurs) profile, exponential disk, and Gaussian or Moffat functions. The azimuthal shapes are generalized ellipses that can fit disk and boxy components. The paper discusses the application of the program in standard modeling of global galaxy profiles, extracting bars, stellar disks, double nuclei, and compact nuclear sources, and measuring absolute dust extinction or surface brightness fluctuations. It also highlights the ability to accurately extract nuclear point sources in galaxies. The authors compare 2-D and 1-D extraction techniques on simulated images and apply the method to nearby galaxies with weak nuclei. The paper includes a detailed discussion of the algorithm's mechanics, computational requirements, and fitting procedures, along with case studies of 7 galaxies to illustrate the versatility of the program.The paper presents GALFIT, a two-dimensional (2-D) fitting algorithm designed to extract structural components from galaxy images, particularly for spatially well-resolved, nearby galaxies observed with the Hubble Space Telescope. The algorithm improves upon previous techniques by allowing simultaneous fitting with an arbitrary number of components and optimizing computation speed for large galaxy images. It uses 2-D models such as the "Nuker" law, Sérsic (de Vaucouleurs) profile, exponential disk, and Gaussian or Moffat functions. The azimuthal shapes are generalized ellipses that can fit disk and boxy components. The paper discusses the application of the program in standard modeling of global galaxy profiles, extracting bars, stellar disks, double nuclei, and compact nuclear sources, and measuring absolute dust extinction or surface brightness fluctuations. It also highlights the ability to accurately extract nuclear point sources in galaxies. The authors compare 2-D and 1-D extraction techniques on simulated images and apply the method to nearby galaxies with weak nuclei. The paper includes a detailed discussion of the algorithm's mechanics, computational requirements, and fitting procedures, along with case studies of 7 galaxies to illustrate the versatility of the program.