PHP File Upload Recognition help! - php

Question

SOLVED MY OWN QUESTION! THANKS EVERYONE FOR THE HELP :)
Ok. I'm having trouble with the code below recognizing the upload FILE TYPE and running the correct function. I can upload PNG just fine and it will convert and resize like it should, but GIF and JPEG don't and just return a black image. If I remove the png code and try the others individually they work. I can't figure this out at the moment why when I combine them they won't work. It's like together they all use whatever function comes first, instead of going by the FILE TYPE
if ($width > $max_width){
$scale = $max_width/$width;
if ($_FILE['image']['type'] = "image/png"){
$uploaded = resizeImagePNG($large_image_location,$width,$height,$scale);
} elseif ($_FILE['image']['type'] = "image/gif"){
$uploaded = resizeImageGIF($large_image_location,$width,$height,$scale);
} elseif ($_FILE['image']['type'] = "image/jpeg" || $_FILE['image']['type'] = "image/pjpeg"){
$uploaded = resizeImageJPG($large_image_location,$width,$height,$scale);
}
session_start();
$_SESSION['image2resize'] = $large_image_location;
}else{
$scale = 1;
if ($_FILE['image']['type'] = "image/png"){
$uploaded = resizeImagePNG($large_image_location,$width,$height,$scale);
} elseif ($_FILE['image']['type'] = "image/gif"){
$uploaded = resizeImageGIF($large_image_location,$width,$height,$scale);
} elseif ($_FILE['image']['type'] = "image/jpeg" || $_FILE['image']['type'] = "image/pjpeg"){
$uploaded = resizeImageJPG($large_image_location,$width,$height,$scale);
}
session_start();
$_SESSION['image2resize'] = $large_image_location;
}
}

Answer 1

edit: combined with Pekka's method for the mime, and rewritten for clarity
You have an error in all your if/elseif comparations. You need to put double == instead of single =
You may use this code that should do the same, but in a cleaner and safer way
$info = getimagesize(($_FILE['image']['tmp_name']);
$mime = $info["mime"];
if ($width > $max_width){
$scale = $max_width/$width;
} else {
$scale = 1;
}
switch ($mime)
{
case "image/png":
$uploaded = resizeImagePNG($large_image_location,$width,$height,$scale);
break;
case "image/gif":
$uploaded = resizeImageGIF($large_image_location,$width,$height,$scale);
break;
case "image/jpeg":
$uploaded = resizeImageJPG($large_image_location,$width,$height,$scale);
break;
default:
// do a better handling of the error
die('image type not supported');
}
session_start();
$_SESSION['image2resize'] = $large_image_location;
Also, don't rely on $_FILE['image']['type'], as this value is sent by the browser and an attacker can forge it. Use the getimagesize() method for obtaining the filetype as Pekka suggested in his answer.

Answer 2

#Carlos answers your question.
As a side note, I wouldn't rely on the MIME type server by the user's browser at all, and use getimagesize() to detect the file type instead.
$info = getimagesize(($_FILE['image']['tmp_name']);
$mime = $info["mime"];
that is safer.

Answer 3

FIGURED IT OUT!!!!!!!! The verification was screwing things up. Instead of checking if it's not a image, I checked if it was and it started working. NEW verification -> if ($mime == 'image/gif' || $mime == 'image/jpeg' || $mime == 'image/pjpeg' || $mime == 'image/png' || $_FILES['image']['size'] < 3000000){ working code here } else { error code here } . Thanks for all the help!