How to automatically fill mockups?

Question

Layouts and prototypes

Good day!

There are two sets of images:
a) Mockups - some images, blanks/templates (for example, an image of a device with a display).
b) Content - what needs to be inserted into mockups (ex. an image of a graph of something changing).

Is there any way to insert each instance of Content into each Mocap and save the result in a separate file?


Note:
1. For each mocap, the place where the Content should be inserted is known.
2. Mockups are in jpeg format (but you can re-save to another one).
3. Mockup and Content, this is not about the iPhone and the site / application, these are other devices, and there are no blanks on the Internet.
4. Both services / finished products and automation scripts will be quite satisfied.

Thank you!