I don't think it is a bug. Icons are special animals, the icon file contains several images at different sizes (because icons are small and resize algorithms generate pixels soup, so the resizing is done "manually"). So when you export, each layer of the image becomes one of the available icon sizes. So when you have several layers:
You are asked which one to include:
And they are all part of the output, at their actual size:
You are asked which one to include:
And they are all part of the output, at their actual size:
Code:
> identify /tmp/Sample.ico
/tmp/Sample.ico[0] ICO 16x16 16x16+0+0 8-bit sRGB 0.000u 0:00.000
/tmp/Sample.ico[1] ICO 32x32 32x32+0+0 8-bit sRGB 0.000u 0:00.000
/tmp/Sample.ico[2] ICO 64x64 64x64+0+0 8-bit sRGB 9326B 0.000u 0:00.000