BCGControlBar Pro for MFC
double CBCGPToolBar::m_dblLargeImageRatio

Specifies the ratio for large images.

The default ratio is 2. You can change this value to make large toolbar images bigger or smaller.

m_dblLargeImageRatio is taken into account only if you do not prepare a special set of large images. For example, if you provide only set of small images with size 16x16 and want the large images with the size 24x24, then you have to set m_dblLargeImageRatio to 1.5.