I'm a newbie in image processing using Mathematica.
I'd like to compose an image $A$ over an image $B$ into an image C such that
$\quad C[i,j] = B[i,j]$, if $A[i,j]$ is white
$\quad C[i,j] = A[i,j]$, otherwise
It would work if I could do
Min on each pixel:
$\quad C[i,j] = \min(A[i,j],B[i,j])$
Min does not seem to work component-wise.
Perhaps I could turn white in $A$ into transparency and then compose over $B$. How can I do this?