Adem Alp YILDIZ

img2ico("icon1.jpg", "icon1.ico");
img2ico("icon2.gif", "icon2.ico");
img2ico("icon3.png", "icon3.ico");

function img2ico($file, $ico)
{
    $type = exif_imagetype($file);
 
    switch ($type)
    {
        case IMAGETYPE_GIF:
            $im = imagecreatefromgif($file);
            break;
        case IMAGETYPE_JPEG:
            $im = imagecreatefromjpeg($file);
            break;
        case IMAGETYPE_PNG:
            $im = imagecreatefrompng($file);
            break;
    }
 
    if (isset($im)) {
        $ima = array($im);
        $gd = GD2ICOstring($ima);
        file_put_contents($ico, $gd);
    }
}
 
function GD2ICOstring(&$gd_image_array)
{
    foreach ($gd_image_array as $key => $gd_image) {
 
        $ImageWidths[$key] = ImageSX($gd_image);
 
        $ImageHeights[$key] = ImageSY($gd_image);
        $bpp[$key] = ImageIsTrueColor($gd_image) ? 32 : 24;
        $totalcolors[$key] = ImageColorsTotal($gd_image);
 
        $icXOR[$key] = '';
        for ($y = $ImageHeights[$key] - 1; $y >= 0; $y--) {
            for ($x = 0; $x < $ImageWidths[$key]; $x++) {
                $argb = GetPixelColor($gd_image, $x, $y);
                $a = round(255 * ((127 - $argb['alpha']) / 127));
                $r = $argb['red'];
                $g = $argb['green'];
                $b = $argb['blue'];
 
                if ($bpp[$key] == 32) {
                    $icXOR[$key] .= chr($b) . chr($g) . chr($r) . chr($a);
                } elseif ($bpp[$key] == 24) {
                    $icXOR[$key] .= chr($b) . chr($g) . chr($r);
                }
                $icANDmask = array();
                if ($a < 128) {
                    @$icANDmask[$key][$y] .= '1';
                } else {
                    @$icANDmask[$key][$y] .= '0';
                }
            }
            // mask bits are 32-bit aligned per scanline
            while (strlen($icANDmask[$key][$y]) % 32) {
                $icANDmask[$key][$y] .= '0';
            }
        }
        $icAND[$key] = '';
        foreach ($icANDmask[$key] as $y => $scanlinemaskbits) {
            for ($i = 0; $i < strlen($scanlinemaskbits); $i += 8) {
                $icAND[$key] .= chr(bindec(str_pad(substr($scanlinemaskbits, $i, 8), 8, '0', STR_PAD_LEFT)));
            }
        }
 
    }
 
    foreach ($gd_image_array as $key => $gd_image) {
        $biSizeImage = $ImageWidths[$key] * $ImageHeights[$key] * ($bpp[$key] / 8);
 
        // BITMAPINFOHEADER - 40 bytes
        $BitmapInfoHeader[$key] = '';
        $BitmapInfoHeader[$key] .= "\x28\x00\x00\x00"; // DWORD  biSize;
        $BitmapInfoHeader[$key] .= LittleEndian2String($ImageWidths[$key], 4); // LONG   biWidth;
        // The biHeight member specifies the combined
        // height of the XOR and AND masks.
        $BitmapInfoHeader[$key] .= LittleEndian2String($ImageHeights[$key] * 2, 4); // LONG   biHeight;
        $BitmapInfoHeader[$key] .= "\x01\x00"; // WORD   biPlanes;
        $BitmapInfoHeader[$key] .= chr($bpp[$key]) . "\x00"; // wBitCount;
        $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00"; // DWORD  biCompression;
        $BitmapInfoHeader[$key] .= LittleEndian2String($biSizeImage, 4); // DWORD  biSizeImage;
        $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00"; // LONG   biXPelsPerMeter;
        $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00"; // LONG   biYPelsPerMeter;
        $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00"; // DWORD  biClrUsed;
        $BitmapInfoHeader[$key] .= "\x00\x00\x00\x00"; // DWORD  biClrImportant;
    }
 
 
    $icondata = "\x00\x00"; // idReserved;   // Reserved (must be 0)
    $icondata .= "\x01\x00"; // idType;       // Resource Type (1 for icons)
    $icondata .= LittleEndian2String(count($gd_image_array), 2); // idCount;      // How many images?
 
    $dwImageOffset = 6 + (count($gd_image_array) * 16);
    foreach ($gd_image_array as $key => $gd_image) {
        // ICONDIRENTRY   idEntries[1]; // An entry for each image (idCount of 'em)
 
        $icondata .= chr($ImageWidths[$key]); // bWidth;          // Width, in pixels, of the image
        $icondata .= chr($ImageHeights[$key]); // bHeight;         // Height, in pixels, of the image
        $icondata .= chr($totalcolors[$key]); // bColorCount;     // Number of colors in image (0 if >=8bpp)
        $icondata .= "\x00"; // bReserved;       // Reserved ( must be 0)
 
        $icondata .= "\x01\x00"; // wPlanes;         // Color Planes
        $icondata .= chr($bpp[$key]) . "\x00"; // wBitCount;       // Bits per pixel
 
        $dwBytesInRes = 40 + strlen($icXOR[$key]) + strlen($icAND[$key]);
        $icondata .= LittleEndian2String($dwBytesInRes, 4); // dwBytesInRes;    // How many bytes in this resource?
 
        $icondata .= LittleEndian2String($dwImageOffset, 4); // dwImageOffset;   // Where in the file is this image?
        $dwImageOffset += strlen($BitmapInfoHeader[$key]);
        $dwImageOffset += strlen($icXOR[$key]);
        $dwImageOffset += strlen($icAND[$key]);
    }
 
    foreach ($gd_image_array as $key => $gd_image) {
        $icondata .= $BitmapInfoHeader[$key];
        $icondata .= $icXOR[$key];
        $icondata .= $icAND[$key];
    }
 
    return $icondata;
}
 
function GetPixelColor(&$img, $x, $y)
{
    if (!is_resource($img)) {
        return false;
    }
    return @ImageColorsForIndex($img, @ImageColorAt($img, $x, $y));
}
 
function LittleEndian2String($number, $minbytes = 1)
{
    $intstring = '';
    while ($number > 0) {
        $intstring = $intstring . chr($number & 255);
        $number >>= 8;
    }
    return str_pad($intstring, $minbytes, "\x00", STR_PAD_RIGHT);
}