You have granted Reddit a perpetual license to them though, so they can keep them if they want
> you agree that by posting messages, uploading files, inputting data, or engaging in any other form of communication with or through the Website, you grant us a royalty-free, perpetual, non-exclusive, unrestricted, worldwide license to use, reproduce, modify, adapt, translate, enhance, transmit, distribute, publicly perform, display, or sublicense any such communication in any medium (now in existence or hereinafter developed) and for any purpose, including commercial purposes, and to authorize others to do so.
> you agree that by posting messages, uploading files, inputting data, or engaging in any other form of communication with or through the Website, you grant us a royalty-free, perpetual, non-exclusive, unrestricted, worldwide license to use, reproduce, modify, adapt, translate, enhance, transmit, distribute, publicly perform, display, or sublicense any such communication in any medium (now in existence or hereinafter developed) and for any purpose, including commercial purposes, and to authorize others to do so.
^Reddit copyright policy