Steam avatar processing bug

[Maleckii]

OK, I'm pretty sure that this is a long standing bug (at least, that's what cursory Internet searches show), and I can't find any possible way it would be a security issue, so I'm reporting it here.

If you set your Steam avatar to an all black BMP, the 184px and 64px versions of the avatar will be set to a blonde woman wearing a T-shirt that says SEND NUDES, but the 32px version will be the correct, black image. This only works with BMP files, and didn't seem to work with a BMP creatd with Paint.NET, only with regular ol' mspaint.exe or Photoshop. I tried different sizes, different bit depths, even OS/2 format BMP images, but any time I set my Steam avatar to a black BMP, I get SEND NUDES girl.

This doesn't work with PNG or other image formats. It also doesn't work if you put a single white pixel in there. It has to be an all black BMP.

I'm sure this can't be an Easter egg, because I don't believe Valve would be this crass. For an example of what this looks like, check out my profile page. As far as I can tell, this is 100% reproducible, and I've tested it with several BMP images and several people's profiles.

[Maleckii]

Here's what it looks like in my profile page.

https://i.imgur.com/gfw8xVg.jpg

[Maleckii]

Also, check this out.

https://i.imgur.com/OdLOZmu.jpg

Something's going on.

[Maleckii]

Steps to reproduce:

1. Create an all black, 100x100 image in MS Paint.
2. Save the image as a BMP. 16-bit BMP worked for me, but I think other types work too.
3. Set the BMP as your steam avatar.
4. Have your mind be blown as all of a sudden your avatar is not a black image, and instead is SEND NUDES T-shirt girl.

[[Max] Stu L Tissimus]

I can confirm I'm also seeing the topic poster with 2 different avatars in this topic