Oh. I'm sorry. I see what you mean. If flag_pic is incremented every time, do me a favor and run this:

if(($row->{image_name_1} ne "") eq ($pics[0] ne "")){
print "IMG NAME is '$image_name_1'\n";
print "PICS-0 is '$pics[0]'\n";
$flag_pic+=1;
}
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This will help in troubleshooting because I am not sure what values to expect for these two variables. Right now you are checking to see:
1. if the image name is not equal to '' (empty string)
AND
2. if the pic is not equal to '' (empty string)
Am I correct in my understanding that $pic[x] #(where x is 0-3) will not usually be an empty string because it's the file the user is trying to upload?
Maybe you want to change your if to evaluate against the image name compared to the picture name?