I have a few remarks om the mirror-function:
The cases horizontal and vertical are switched.
1 = vertical and 2 = horizontal.
When I used it there appeared a black lining of 1 pixel on the side or on the top of the picture.
To remove it the function becomes as follows:

<?php
function ImageFlip ( $imgsrc, $mode )
{

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

    $src_x                        =    0;
    $src_y                        =    0;
    $src_width                    =    $width;
    $src_height                   =    $height;

    switch ( $mode )
    {

        case '1': //vertical
            $src_y                =    $height -1;
            $src_height           =    -$height;
        break;

        case '2': //horizontal
            $src_x                =    $width -1;
            $src_width            =    -$width;
        break;

        case '3': //both
            $src_x                =    $width -1;
            $src_y                =    $height -1;
            $src_width            =    -$width;
            $src_height           =    -$height;
        break;

        default:
            return $imgsrc;

    }

    $imgdest                    =    imagecreatetruecolor ( $width, $height );

    if ( imagecopyresampled ( $imgdest, $imgsrc, 0, 0, $src_x, $src_y , $width, $height, $src_width, $src_height ) )
    {
        return $imgdest;
    }

    return $imgsrc;

}
?>