This is my 'perfect' (i use that word lightly) thumbnail generation script, switch '$transparency' to true to have it do its best to handle transparency in gifs and pngs. this code is built off of comments and advice of everyone else here, and i do not deserve full credit. So far this handles every error i can throw at it.
<?php
function createthumb($name, $newname, $new_w, $new_h, $border=false, $transparency=true, $base64=false) {
if(file_exists($newname))
@unlink($newname);
if(!file_exists($name))
return false;
$arr = split("\.",$name);
$ext = $arr[count($arr)-1];
if($ext=="jpeg" || $ext=="jpg"){
$img = @imagecreatefromjpeg($name);
} elseif($ext=="png"){
$img = @imagecreatefrompng($name);
} elseif($ext=="gif") {
$img = @imagecreatefromgif($name);
}
if(!$img)
return false;
$old_x = imageSX($img);
$old_y = imageSY($img);
if($old_x < $new_w && $old_y < $new_h) {
$thumb_w = $old_x;
$thumb_h = $old_y;
} elseif ($old_x > $old_y) {
$thumb_w = $new_w;
$thumb_h = floor(($old_y*($new_h/$old_x)));
} elseif ($old_x < $old_y) {
$thumb_w = floor($old_x*($new_w/$old_y));
$thumb_h = $new_h;
} elseif ($old_x == $old_y) {
$thumb_w = $new_w;
$thumb_h = $new_h;
}
$thumb_w = ($thumb_w<1) ? 1 : $thumb_w;
$thumb_h = ($thumb_h<1) ? 1 : $thumb_h;
$new_img = ImageCreateTrueColor($thumb_w, $thumb_h);
if($transparency) {
if($ext=="png") {
imagealphablending($new_img, false);
$colorTransparent = imagecolorallocatealpha($new_img, 0, 0, 0, 127);
imagefill($new_img, 0, 0, $colorTransparent);
imagesavealpha($new_img, true);
} elseif($ext=="gif") {
$trnprt_indx = imagecolortransparent($img);
if ($trnprt_indx >= 0) {
$trnprt_color = imagecolorsforindex($img, $trnprt_indx);
$trnprt_indx = imagecolorallocate($new_img, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);
imagefill($new_img, 0, 0, $trnprt_indx);
imagecolortransparent($new_img, $trnprt_indx);
}
}
} else {
Imagefill($new_img, 0, 0, imagecolorallocate($new_img, 255, 255, 255));
}
imagecopyresampled($new_img, $img, 0,0,0,0, $thumb_w, $thumb_h, $old_x, $old_y);
if($border) {
$black = imagecolorallocate($new_img, 0, 0, 0);
imagerectangle($new_img,0,0, $thumb_w, $thumb_h, $black);
}
if($base64) {
ob_start();
imagepng($new_img);
$img = ob_get_contents();
ob_end_clean();
$return = base64_encode($img);
} else {
if($ext=="jpeg" || $ext=="jpg"){
imagejpeg($new_img, $newname);
$return = true;
} elseif($ext=="png"){
imagepng($new_img, $newname);
$return = true;
} elseif($ext=="gif") {
imagegif($new_img, $newname);
$return = true;
}
}
imagedestroy($new_img);
imagedestroy($img);
return $return;
}
createthumb("img.gif", "tn_img.gif", 64,64,true, true, false);
?>