Acces thumbnail images for PDFs

I'm using Dropbox to store PDF files, and my external application needs to programmatically access a thumbnail image of the first page for each of these PDF files.

 

These thumbnail images need to be inserted into emails, so I think the Embedder functionality will not be suitable for this use case?

 

Is there a way to directly access the thumbnail that Dropbox generates for each file via http?

 

If not, is there a suggested/recommended approach to convert PDF to an image format and use that for a thumbnail?

 

Thanks