I'm making an infographic and have found that the best way to make a vector of something is to start with a real something and basically make it monocolor (all black, or all blue). I am wondering if this is ok? The infographic is for work but we are a nonprofit.
No. Even using some autmated raster to vector conversion is merely creating a derivative work.
If you don't own the original image, there is nothing you can do to make an existing copyright null and void.
Changing color, size, or other image qualities are all seen a derivative works and would not free you from any copyright claims.
Safest bet.. if you didn't take a photo and there is no declarative statement allowing reuse... then you can't use it.
Kind of Bloop's album art is a good test case for what you're after.
The important part:
I'd recommend against using a photo as the starting point for any design, no matter how much you think you're going to alter it.