1. A system for backing up a virtual machine disk file in a virtual computing environment, the system comprising: a computer system comprising computer hardware, the computer system comprising a data store, the computer system programmed to implement a cataloging module, a backup module, and a restore module, wherein: the cataloging module is configured to, for each virtual machine disk file of a plurality of virtual machine disk files: access the virtual machine disk file comprising a file system of a guest operating system of a virtual machine to obtain metadata about the file system, the metadata comprising information about a logical structure of the file system; analyze the metadata to determine a logical hierarchy of a set of files in the file system; analyze the metadata to determine one or more attributes of the set of files in the file system; generate a catalog comprising information about the logical hierarchy and the one or more attributes of the set of files in the file system, the catalog comprising a computer-enabled searchable index of at least one of a plurality of image-based backups, wherein the computer-enabled searchable index performs automated file searches within the plurality of image-based backups without manually mounting a backup image containing a searched-for file; wherein each image-based backup of the plurality of image-based backups is associated with a unique catalog; and store the catalog outside the virtual machine; the backup module is configured to, for each virtual machine disk file of the plurality of virtual machine disk files: backup the virtual machine disk file to a backup image stored on the data store; and the restore module is configured to: enable a user to search the catalogs for a desired file from a virtual machine image-based backup from outside the virtual machines and without specifying which virtual machine image includes the desired file; and wherein the computer system is programmed to concurrently and asynchronously execute the cataloging module in a first thread and the backup module in a second thread different from the first thread, wherein the cataloging module is configured to determine the logical hierarchy of the at least some files in the file system in a first pass through the metadata and to determine the one or more attributes of the at least some files in the file system in a second pass through the metadata; and wherein the first thread and the second thread are executed by a backup server outside the virtual machine associated with the virtual machine disk file.