ofSaveImage & ofFloatImage outputs noise

Hi
when I use the save method of ofFloatImage with a buffer I only get noise.

Maybe I am doing something wrong.

This one outputs white noise:

ofFloatImage pix_img_out;
ofBuffer imgOut;
pix_img_out.save( imgOut, OF_IMAGE_FORMAT_PNG, OF_IMAGE_QUALITY_BEST );
ofFile pixFile = ofFile(args.getFilename(), ofFile::ReadWrite);
pixFile.writeFromBuffer(imgOut);

actually the problem might be in the ofSaveImage function. The following example does not work:

ofFloatImage pix_img_out;

ofBuffer imageBuffer;
ofSaveImage(pix_img_out.getPixels(), imageBuffer);  // <<<< here
ofFile pixFile = ofFile(args.getFilename(), ofFile::ReadWrite);
pixFile.writeFromBuffer(imageBuffer);

I had to get the pixels and then save the pixels to a buffer. This one does work:

ofFloatImage pix_img_out; 
ofPixels pixels = pix_img_out.getPixels(); // <<< pixels declared and I assume copied

ofBuffer imageBuffer;
ofSaveImage(pixels, imageBuffer); <<< works
ofFile pixFile = ofFile(args.getFilename(), ofFile::ReadWrite);
pixFile.writeFromBuffer(imageBuffer);

Reproduce the two examples using ofFloatImage::save and ofSaveImage, comparing the buffer produced from ofFloatImage pixels with the buffer produced from copied ofPixels. Trace the relevant overloads and verify that the resulting file is a valid, correctly rendered PNG rather than noise.