I have been looking into icon sizes and DPI and have found the following I need help understanding.

The following 2 screen shots show a toolbar icon showing it's size, a view showing images on buttons and a view showing images on tab buttons. The first image is 100% DPI and the second is 125% with no code changes.

The icon I'm using is the DAW test icon - all.ico

Click image for larger version. 

Name:	dpi100.png 
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ID:	10906

Click image for larger version. 

Name:	dpi125.png 
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Size:	33.0 KB 
ID:	10907

Note the toolbar icon in 100% uses the 16x16 size and in 125% it uses the 24x24 size, which is expected.


1, the tab button icons just seem to be sized 16x16 but uses 32 (100%) and 48 (125%) - why does the image change? and why doesn't it use 16? The tab dialog image list image height and width is 16.

2, same with the button why does the image change from 32 to 48, and how does it choose those images? Also the piImageSize seems to have no baring either, on selecting a size within the icon set.