Question

I upload the image to my site. Image has width is 498 and height is 402.
I need to make a preview image with the established maximum width of 250px and a maximum height of 250px, but the image should be 250 to 250, and must be proportional to the width of 250 pixels.

How to do it?

EDIT

I upload images to your server. The limit on the size I want to make 250 in width and 250 in height.
This does not mean that if I upload an image 1000h500, then it must do 250×250, which means that the width we’re doing 250 pixels and the height is proportional to the first dimension is 125. In the end, I should get a picture 250×125.
Second example: I have an image 100h800. I mean it should be changed

Answer 1

function makeThumbnail($image, $dest)
    {
        $imageType = exif_imagetype($image);

        switch ($imageType)
        {
            case IMAGETYPE_JPEG:
                $img = imagecreatefromjpeg($image);
                break;
            case IMAGETYPE_PNG:
                $img = imagecreatefrompng($image);
                break;
            case IMAGETYPE_GIF:
                $img = imagecreatefromgif($image);
                break;
            default:
                throw new Im_Exception('Bad extension');
        }

        $width  = imagesx($img);
        $height = imagesy($img);        

        if ($height > $width) 
        {   
            $ratio = 250 / $height;  
            $newHeight = 250;
            $newWidth = $width * $ratio; 
        }
        else
        {
            $ratio = 250 / $width;   
            $newWidth = 250;  
            $newHeight = $height * $ratio;   
        }

        $previewImg = imagecreatetruecolor($newWidth, $newHeight); 

        $palsize = ImageColorsTotal($img); 
        for ($i = 0; $i < $palsize; $i++) 
        { 
            $colors = ImageColorsForIndex($img, $i);   
            ImageColorAllocate($previewImg, $colors['red'], $colors['green'], $colors['blue']);
        } 

        imagecopyresized($previewImg, $img, 0, 0, 0, 0, $newWidth, $newHeight, $width, $height);

        switch ($imageType)
        {
            case IMAGETYPE_JPEG:
                $ext = 'jpg';
                imagejpeg($previewImg, $dest . '.' . $ext);
                break;
            case IMAGETYPE_PNG:
            case IMAGETYPE_GIF:
                $ext = 'png';
                imagesavealpha($previewImg, true);
                imagepng($previewImg, $dest . '.' . $ext, 9);
                break;
            default:
                throw new Im_Exception();
        }
        imagedestroy($previewImg);
        imagedestroy($img);
    }