Large Images Rejected

[BradanCraig]

I am working with large grayscale images with sizes ~50,000 x ~10,000. When trying to load the image, it returns an error "qt.gui.imageio: QImageIOHandler: Rejecting image as it exceeds the current allocation limit of 128 megabytes".

I beleive the error comes from the lines 126 & 127 of label_img.cpp as it automatically converts to RGB888 making my image take up 24x memory.
'''
m_inputImg = img.copy();
m_inputImg = m_inputImg.convertToFormat(QImage::Format_RGB888)
'''