$list = getimagesize($imagePath);
$width = $list[0];
$height = $list[1];

$height = round(($height * $width) / $width);

list($Width, $Height) = getimagesize($row["img_file"]);

    if(($Width > $Height) && ($Width > 115))
    {
        $Height = ceil(($Height / $Width) * 115) ;
        $Width = 115;
    }
    elseif(($Height > $Width) && ($Height > 115))
    {
        $Width = ceil(($Width / $Height)* 115);
        $Height = 115;
    }
    elseif(($Height > 115) && ($Height == $Width))
    {
        $Height = 115;
        $Width = 115;
    }

if ($extension == "png")
        {
            $image = imagecreatefrompng($URLofImage)or die("Width Of Image: ".$widthofImage." Height Of Image: ".$heightofImage." Height: ".$height." Width: ".$width);
            $image_p = imagecreatetruecolor($widthofImage, $heightofImage)or die("Width Of Image: ".$widthofImage." Height Of Image: ".$heightofImage." Height: ".$height." Width: ".$width);
            imagealphablending($image_p, false);
            $color = imagecolorallocatealpha($image_p, 0, 0, 0, 0);
            imagesavealpha($image_p, true);
            list($width, $height) = getimagesize($URLofImage);

            imagecopyresampled($image_p, $image, 0, 0, 0, 0, $widthofImage, $heightofImage, $width, $height);
            imagepng($image_p, "./images/thumbs/".$name, 9);

            return ("./images/thumbs/".$name);
        }

$max_width = 115;
$max_height = 115;

list($width, $height) = getimagesize($imagePath);
$ratioh = $max_height/$height;
$ratiow = $max_width/$width;
$ratio = min($ratioh, $ratiow);

// New dimensions
$width = intval($ratio * $width);
$height = intval($ratio * $height);

$max_height = 115;
if ($height > $max_height)
{
    $scale = $max_height / $height;
    $height = intval($height * $scale);
    $width  = intval($width  * $scale);
}

$max_size = 115;
if (max($height, $width) > $max_size)
{
    $scale = $max_size / max($height, $width);
    $height = intval($height * $scale);
    $width  = intval($width  * $scale);
}

<img alt='image alt' src='imagesrc' style='max-width:115px; max-height:115px; height:auto; width:auto;' />