# QLThumbnailImageCreate(_:_:_:_:) Creates a thumbnail image for the specified file. ``` func QLThumbnailImageCreate(_ allocator: CFAllocator!, _ url: CFURL!, _ maxThumbnailSize: CGSize, _ options: CFDictionary!) -> Unmanaged! ``` ## Parameters `allocator` The allocator to use to create the thumbnail image. `url` The URL of the file to create a thumbnail image for. `maxThumbnailSize` The maximum desired size of the thumbnail image. `options` A dictionary of options that affect the creation of the thumbnail image. You can use [`kQLThumbnailOptionIconModeKey`](/documentation/QuickLook/kQLThumbnailOptionIconModeKey) and [`kQLThumbnailOptionScaleFactorKey`](/documentation/QuickLook/kQLThumbnailOptionScaleFactorKey) as options. ## Return Value The thumbnail image, or `NULL` if Quick Look doesn’t support this file type. ## Discussion This function doesn’t supplant the use of Icon Services by apps to get generic file icons and custom icons stored in the metadata fork of files. ### Special Considerations This function is thread-safe, so you can call it from any thread. However, because it’s synchronous, you should generally call it in a background thread. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)