GD library perform differently in the server - php

Question

I have a problem in my images using the GD library in my live site.
Is there an issue of GD library in linux? I implemented the resizing and cropping of image using the GD library, but somehow only the resizing works. Also, png images have black background after resized. My codes are working totally fine in local but not in my hosted site. I didn't get any errors so I am not sure where the problem is.
This is my code:
$info = getimagesize($src);
$source_image = '';
if ($info['mime'] == 'image/jpeg')
$source_image = imagecreatefromjpeg($src);
elseif ($info['mime'] == 'image/gif')
$source_image = imagecreatefromgif($src);
elseif ($info['mime'] == 'image/png')
$source_image = imagecreatefrompng($src);
$cropped = imagecropauto($source_image, IMG_CROP_DEFAULT);
if ($cropped !== false) {
imagedestroy($source_image);
$source_image = $cropped;
}
$width = imagesx($source_image);
$height = imagesy($source_image);
$maxHeight = floor($height * ($maxWidth / $width));
$dst = imagecreatetruecolor($maxWidth, $maxHeight);
$background = imagecolorallocate($dst, 0, 0, 0);
imagecolortransparent($dst, $background);
imagealphablending($dst, false);
imagesavealpha($dst,true);
imagecopyresampled($dst, $source_image, 0, 0, 0, 0, $maxWidth, $maxHeight, $width, $height);
if ($info['mime'] == 'image/jpeg')
imagejpeg($dst, $newFilename);
elseif ($info['mime'] == 'image/gif')
imagegif($dst, $newFilename);
elseif ($info['mime'] == 'image/png')
imagepng($dst, $newFilename);
Please help. Thank You

Answer 1

Replace IMG_CROP_DEFAULT with IMG_CROP_SIDES
also read documentation click here you also fill color using
<?php
// Create a 300x300px transparant image with a 100px wide red circle in the middle
$i = imagecreatetruecolor(300, 300);
imagealphablending($i, FALSE);
imagesavealpha($i, TRUE);
$transparant = imagecolorallocatealpha($i, 0xDD, 0xDD, 0xDD, 0x7F);
imagecolortransparent($i, $transparant); // Set background transparent
imagefill($i, 0, 0, $transparant);
$red = imagecolorallocate($i, 0xFF, 0x0, 0x0);
imagefilledellipse($i, 150, 150, 100, 100, $red);
imagepng($i, "red_300.png");
// Crop away transparant parts and save
$i2 = imagecropauto($i, IMG_CROP_DEFAULT); //Attempts to use IMG_CROP_TRANSPARENT and if it fails it falls back to IMG_CROP_SIDES.
imagepng($i2, "red_crop_trans.png");
imagedestroy($i2);
// Crop away bg-color parts and save
$i2 = imagecropauto($i, IMG_CROP_SIDES);
imagepng($i2, "red_crop_sides.png");
imagedestroy($i2);
// clean up org image
imagedestroy($i);
?>