MOSAIC is a versatile image processing and analysis software package written in IDL, designed for the manipulation of image data obtained with infrared array detectors, such as CanariCam or T-ReCS. The package provides methods for processing, calibration, analysis, and visualization of astronomical image data, stressing effective methods for the creation of mosaics from collections of exposures, while preserving the photometric integrity of the original data. Additional analysis features include deconvolution of images, and the modeling of dust masses with one or two emission temperatures in a multi-wavelength stack of images, by robust non-linear fitting of silicate/carbon dust models to fluxes in apertures or for all pixels in the images. The MOSAIC package is available at http://www.astro.ufl.edu/~varosi/mosaic.