A thumbnail preview of a file enables a user to recognize the file without opening it. An algorithmic approach to generating simulated thumbnail previews is provided. This approach includes executing rules for determining and implementing one or more rendering schemas to simulate different content types within a portion of a file. A simulated thumbnail preview is generated from the simulated content types based on a file structure. Since users may rely on the general structure and distinguishing content elements of a thumbnail for recognizing a file, these distinguishing elements are maintained based on different rendering schemas used to create a simulated thumbnail. Moreover, the algorithmic approach promotes consistent simulated thumbnails across clients, regardless of client processing capabilities, form factors, customized theming, or the like. Based on the rules for rendering various content types, the simulated thumbnails are also consistently generated across documents.