Problem with Orthanc read

Orthanc has a read series which works fine under ImageJ but fails under Fiji. I tracked it down to

public BufferedImage ReadImage(String uri) throws IOException
    // Ask the download of "image/png", otherwise an "image/jpeg" is negociated
    return, "image/png"));

The works under ImageJ but fails under Fiji. In the end the problem was with bio-formats.
Apparently the original ImageIO is not used but 2 jai_imageio*.jar override the Java default.
As soon as I removed these 2 files, Orthanc started to work properly, like in ImageJ.

Is it possible to modify these jar files so that they let the original do the work?