This document discusses methods for determining membership function values in a fuzzy relational database to optimize image retrieval. It provides an overview of fuzzy relational databases and how they extend conventional databases to allow for imprecise data represented as fuzzy sets. Previous work on a fuzzy database implementation is described that assigns random membership values and adjusts them based on user feedback. Machine learning methods are discussed for automatically improving the membership values through experience. Different methods for constructing membership functions are outlined, including the fuzzy linguistic approach of using natural language terms defined by a user community. The goal is to determine the best approach for setting membership values to satisfy the most users.