15. A system, comprising: a processor; and a memory hosting an application, which, when executed on the processor, performs an operation for encrypting a first application data file, the operation comprising: determining a file format of the first application data file, encrypting the first application data file, selecting a second application data file template having a file format matching the file format of the first application data file, wherein a placeholder image is embedded in the second application data file template, storing the first application data file as encrypted content in an image file container, wherein storing the first application data file as the encrypted content in the image file container comprises: generating the image file container having a first image format; and embedding the encrypted content, as image data, in the image file container; replacing the placeholder image in the second application data file template with the image file container storing the first application data file as encrypted content, embedding, in the second application data file template, textual instructions for accessing the encrypted content, and generating a second application data file from the second application data file template, wherein the textual instructions are presented to users when accessing the second application data file.
19. The system of claim 15 , wherein the first application data file is encrypted and stored in response to determining that the first application data file is to be published to a hosted storage service.