Flickr implemented a simple large “Choose photos and videos” link which when clicked, opens a multi-select-capable file-selection dialog driven by the YUI Uploader. The user can add and remove files as they like according to business logic, configure upload options and so on. Once the user has prepared their selection of files and clicked “Upload Photos and Videos”, the file queue is processed. YUI Uploader can upload files simultaneously or in sequence to a given URL (a signed API call in Flickr’s case) with callbacks for file progress, errors, file completion and upload completion.

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