A user-facing front end screen display of an illustrative digital image painting application includes a bucket tool which enables a user to apply a selected color to a selected area of an uploaded digital image such as a wall of a room, a paint brush tool to fill in missed areas, an eraser tool is to remove misapplied color, masking tools to mask off selected areas, and a tolerance slider tool to assist in properly filling in painted areas. Improved image preprocessing methods enable better definition of areas of the image to be painted the same color.