如何使用PHP将任何图像转换为JPG或JPEG - How to convert any image to JPG or JPEG using PHP

How to convert any image to JPG or JPEG using PHP

可能重复：
使用php gd2 将图像从一种格式保存到另一种格式

我正在将任何图像格式转换为JPEG或JPG。将图像转换为jpg的代码为

function converttojpg($originalimg)
{
$filetype = @end(explode(".", $originalimg));
echo $originalimg . " asdasdfs";
if (strtolower($filetype) == 'jpg' or strtolower($filetype) == 'jpeg') 
    {
    $srcImg = imagecreatefromjpeg($originalimg);
    imagejpeg($srcImg,$originalimg,100);
    imagedestroy($srcImg);
    } 
if (strtolower($filetype) == 'png') 
    {
    $srcImg = imagecreatefrompng($originalimg);
    imagejpeg($srcImg,$originalimg,100);
    imagedestroy($srcImg);
    } 
if (strtolower($filetype) == 'gif') 
    {
    echo "executed";
    $srcImg = imagecreatefromgif($originalimg);
    imagejpeg($srcImg,$originalimg,100);
    imagedestroy($srcImg);
    }
}

之后，我调整转换后的图像的大小，其代码为

function resizeImage($originalImage,$toWidth,$toHeight)
{
// Get the original geometry and calculate scales
list($width, $height) = getimagesize($originalImage);
$xscale=$width/$toWidth;
$yscale=$height/$toHeight;
// Recalculate new size with default ratio
if ($yscale>$xscale)
    {
    $new_width = round($width * (1/$yscale));
    $new_height = round($height * (1/$yscale));
    }
else 
    {
    $new_width = round($width * (1/$xscale));
    $new_height = round($height * (1/$xscale));
    }
// Resize the original image
$imageResized = imagecreatetruecolor($new_width, $new_height);
$imageTmp     = imagecreatefromjpeg ($originalImage);
imagecopyresampled($imageResized, $imageTmp, 0, 0, 0, 0, $new_width, $new_height, $width, $height           );
return $imageResized;
}

在每张图像上，它都会报告错误和警告

    Warning: imagecreatefromjpeg() [function.imagecreatefromjpeg]: gd-jpeg, libjpeg: recoverable error: Corrupt JPEG data: 9 extraneous bytes before marker 0xd9 in E:'xampp'htdocs'photo'functions.php on line 33
Warning: imagecreatefromjpeg() [function.imagecreatefromjpeg]: 'userphotos/corrupted_image_1.jpg' is not a valid JPEG file in E:'xampp'htdocs'photo'functions.php on line 33
Warning: imagejpeg() expects parameter 1 to be resource, boolean given in E:'xampp'htdocs'photo'functions.php on line 34
Warning: imagedestroy() expects parameter 1 to be resource, boolean given in E:'xampp'htdocs'photo'functions.php on line 35
Warning: imagecreatefromjpeg() [function.imagecreatefromjpeg]: gd-jpeg, libjpeg: recoverable error: Corrupt JPEG data: 9 extraneous bytes before marker 0xd9 in E:'xampp'htdocs'photo'functions.php on line 22
Warning: imagecreatefromjpeg() [function.imagecreatefromjpeg]: 'userphotos/53.jpg' is not a valid JPEG file in E:'xampp'htdocs'photo'functions.php on line 22
Warning: imagecopyresampled() expects parameter 2 to be resource, boolean given in E:'xampp'htdocs'photo'functions.php on line 23
userphotos/MG_diesel-04.gif_thumb.png asdasdfsuserphotos/Porsche_911_996_Carrera_4S.jpg asdasdfs

请帮我解决那个问题。我必须完成它。

不要使用扩展名来确定文件类型。要检查给定的文件是否是图像，并且其格式允许GD对其进行操作，请使用getimagesize

<?php
    $image = @imagecreatefromstring(file_get_contents($file_path));
        if ($image === false) {
            throw new Exception (sprintf('invalid image or file not found, file=%s', $file_path));
        }
?>

imagecreatefromstring检测图像类型并创建图像资源，否则将引发异常。