I've created a macro with a button, I'm trying to change the icon to a custom image. Here is the image I'd like to use
I've also attached the bmp file. For some reason when I try to change the icon to my custom bmp, it just reverts to the default icon (see below) 
The solidworks documentation says
- 16 x 16 px
- .bmp
- white background
- 256 colour palette
Are required for icons. (Incidentally, I tried a random bmp from the internet and that worked fine despite not being 16x16 px)
My image (I think) meets all of these; bmp yes, 16x16 yes, white background yes? (Bmps don't have multiple layers so I assume it just means the image has a white background, not that there is some additional background layer which must be right) 256 colour palette - my image only has 150 something colours but it does have an 8 bit palette (according to windows explorer)
Specs:
SW 2017, Win 10, image created in GIMP as indexed image and exported with default bmp settings