Using BibLaTeX fields to reference other files

I’ve got a bibliography which is almost entirely images. Most of those images, and their citations, are going to be referenced in full-page figures at the end of a document. I’m looking to make the below template into its own command,

begin{figure}
  includegraphics[width=textwidth]{path/to/image}
  caption[Short Caption]{A much longer, wordier caption.label{ref:caption}
      fullcite{ct:citation}}
end{figure}

My question about BibLaTeX is: can I avoid supplying path/to/image as an argument to that command? Each of my .bib entries already contains — thanks to BibDesk — relative and absolute paths to the files in the field Bdsk-File-1. There’s some work to get them back out again, but let’s pretend that the bib file has been preprocessed to add a Path-To-Image field. Assuming that field existed, how could I extract it with BibLaTeX and use it as an argument to includegraphics?