C++17 Variable seems to be changed inside if statement

I have a weird bug in my code that I can't make any sense of. I have a variable with an assigned value prior the conditional statement. Somehow the variable is assigned the value it is being compared to inside the if statement.

At first I thought it was just my mistake using '=' instead of '==' but that's not the case.

Here is my debug screens before stepping into the conditional

see that px and img[y][x] are both 1.

Now as soon as I step into the if statement, it all changes to 0 and I get stuck inside the while loop.

Can anyone please explain what happened between these steps? In my debugging, it jumps straight from line 227 to 229 in a single step so I don't know what is happening in between. Also, once it enters the while loop, the only variable I see are x, y, and x0. Shouldn't px and img still exist in this scope?

Is there a better way to approach this? I just want to make sure that my start point is actually a white pixel before I start counting the blanks.

I'm using VC15 if that's of any relevance.