A method performed by a data processing apparatus, the method comprising: determining page resources of a website that each include a plurality of persistent visual resources, each persistent visual resource being a visual resource that is displayed each time the page resource is displayed at a user device; for each of the determined page resources of a website, generating one or more animation snippets from the plurality of persistent visual resources, comprising, for each of the one or more animation snippets: selecting a subset of the persistent visual resources; from each of the selected persistent visual resources, generating an image frame; and generating an animation snippet for the page resource, including: determining, for the page resource of a website, a resource topic to which the subject matter of the page resource is descriptive; and categorizing the animation snippet as belonging to the resource topic, wherein the animation snippet includes each of the image frames generated from the selected persistent visual resources and that displays the image frames in a specific order; for a page resource of a website for which one or more animation snippets have been generated, selecting one of the animation snippets for display as a search result that identifies the page resource as being responsive to a search query, wherein the selecting is based on a match between a topic for the search query and the resource topic that the one of the animation snippets was categorized as belonging to; and providing the selected animation snippet to a user device from which the search query was submitted. determining page resources of a website that each include a plurality of persistent visual resources, each persistent visual resource being a visual resource that is displayed each time the page resource is displayed at a user device; for each of the determined page resources of a website, generating one or more animation snippets from the plurality of persistent visual resources, comprising, for each of the one or more animation snippets: selecting a subset of the persistent visual resources; from each of the selected persistent visual resources, generating an image frame; and generating an animation snippet for the page resource, including: determining, for the page resource of a website, a resource topic to which the subject matter of the page resource is descriptive; and categorizing the animation snippet as belonging to the resource topic, wherein the animation snippet includes each of the image frames generated from the selected persistent visual resources and that displays the image frames in a specific order; selecting a subset of the persistent visual resources; from each of the selected persistent visual resources, generating an image frame; and generating an animation snippet for the page resource, including: determining, for the page resource of a website, a resource topic to which the subject matter of the page resource is descriptive; and categorizing the animation snippet as belonging to the resource topic, wherein the animation snippet includes each of the image frames generated from the selected persistent visual resources and that displays the image frames in a specific order; determining, for the page resource of a website, a resource topic to which the subject matter of the page resource is descriptive; and categorizing the animation snippet as belonging to the resource topic, wherein the animation snippet includes each of the image frames generated from the selected persistent visual resources and that displays the image frames in a specific order; for a page resource of a website for which one or more animation snippets have been generated, selecting one of the animation snippets for display as a search result that identifies the page resource as being responsive to a search query, wherein the selecting is based on a match between a topic for the search query and the resource topic that the one of the animation snippets was categorized as belonging to; and providing the selected animation snippet to a user device from which the search query was submitted.