Write Raw Binary to System Phonegap / Cordova file

I am using an API in my application that returns an image in binary. I am trying to write this to a file using cordova fileWriter.

Assuming the var data

returned binary contains. I can successfully write this to the filesystem ( writer.write(data);

). However, the image is damaged and won't open.

Do I need to do something with the data received before writing it? Maybe turn it into something ?, I'm not familiar with binary data management. Would be grateful for any help