Extract JPEG data without file output

[mklawler]

Would love to be able to get JPEG data from NEF files and use that in-memory data to display in an existing electron window. Seems like I have to write to file and read from file.

[mceachen]

Electron is a bear to get packaged cross-platform.

Once it's there, you'll need to do a .read() call to see what embedded images are available, and then extract the preview: https://photostructure.github.io/exiftool-vendored.js/#md:extracting-embedded-images