Did you create this image while logged in? If so, you can delete it yourself by clicking the "Delete Image" button on the image page.
If you do not have the link to the image you want deleted, you can try searching for the text content of the image on Google using quotes, e.g. "MY IMAGE TEXT". If you don't find it, that means no one can find it using Google search. Images on Imgflip that do not receive many views are deleted automatically, so if the Imgflip link was never shared then our system will delete the image at some point.