BCGControlBar Pro for MFC
BOOL CBCGPToolBarImages::SmoothResize ( double  dblImageScale,
BOOL  bCheckDPIAwareness = TRUE 
)

Uses bicubic algorithm to resize toolbar images.

Parameters
dblImageScaleThe image scaling coefficient. If dblImageScale is less than 1, the size of pictures is reduced.
bCheckDPIAwarenessIf this parameter is FALSE, the image is resized even if the image list is DPI PM2-aware.