Why do image lists and tool bars use horizontal strips if vertical is so much better?
Two people pointed out that the
ImageList_Add function and toolbars use horizontal strips even though we learned that vertical strips are much more efficient. While it’s true that the images are passed to the
CreateToolbarEx functions in horizontal strips, the image list and toolbar code copy them to a vertical strip.
In other words, the horizontal strip is merely an interchange format. Internally, the image list and toolbar use the more efficient vertical arrangement.