Same here, no image type works (jpg, gif, bmp, pdf, svg, png) and although I thank @dezzy for attempting to post a solution, the explanation itself assumes that you
a) know how to convert an image into BASE64 and…
b) know where the ‘pdf’ is and how to insert the raw data into it.
Other than that, good job. Is this likely to be an easy fix? Did it work before?
Many thanks for providing this free though, a little more work and many people would be happy to pay for it.