I consider two basic logics on the idea how to rotate images on the site.

• Change image every time site is loaded. This logics can be realized with the simple php script.

  $results = array();
  $handler = opendir("banner");
  
  while ($file = readdir($handler)) {
          if ($file != "." && $file != "..") {
                     $results[] = $file;
          }
  }
  $banner_num = rand(0, count($results)-1);
  print '';
  

  In this example, we just place all needed pictures to directory banner/. Script reads the list of files from the directory and converts the list to an array. Then we randomly take index of array item and show it on the page.

• Another way is to use simple jquery plugin for rotating images.
  Here is a wonderful simple jQuery script for rotating images on site.
  We can combine previous php example and this script.

  $results = array();
  $handler = opendir("banner");
  print '

  '; while ($file = readdir($handler)) { if ($file != "." && $file != "..") { print '
  • '; print ''; print '
  '; } } print '
  ';

  Then get needed files from here.
  Place the following code in
  

  At the end of file (before ) add the following code:

  
  Note: On IE7 there appear floating caption section even in case there is no caption set. To resolve this issue, add "height: '0px'" as parameter.
  

It took me long time to create an universal function which would create thumbnails from pictures and suit all my needs.
The base for this function, I took from here.
But I modified it slightly.

function createthumb($name, $newname, $new_w, $new_h, $by_small=true, $border=false, $transparency=true, $base64=false) {
    if(file_exists($newname))
        @unlink($newname);
    if(!file_exists($name))
        return false;
    $arr = split("\.",$name);
    $ext = $arr[count($arr)-1];

    if(preg_match('/jpeg/i', $ext)){
        $img = @imagecreatefromjpeg($name);
    }elseif (preg_match('/jpg/i', $ext)){
        $img = @imagecreatefromjpeg($name);
    } elseif(preg_match('/png/i', $ext)){
        $img = @imagecreatefrompng($name);
    } elseif(preg_match('/gif/i', $ext)) {
        $img = @imagecreatefromgif($name);
    }
    if(!$img)
        return false;
    $old_x = imageSX($img);
    $old_y = imageSY($img);
    if($old_x  $old_y) {
        if ($by_small) {
                $thumb_w = floor($old_x*($new_w/$old_y));
                $thumb_h = $new_h;
        }
    } elseif ($old_x == $old_y) {
        $thumb_w = $new_w;
        $thumb_h = $new_h;
    }
    $thumb_w = ($thumb_w= 0) {
                //its transparent
                $trnprt_color = imagecolorsforindex($img, $trnprt_indx);
                $trnprt_indx = imagecolorallocate($new_img, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);
                imagefill($new_img, 0, 0, $trnprt_indx);
                imagecolortransparent($new_img, $trnprt_indx);
            }
        }
    } else {
        Imagefill($new_img, 0, 0, imagecolorallocate($new_img, 255, 255, 255));
    }

    imagecopyresampled($new_img, $img, 0,0,0,0, $thumb_w, $thumb_h, $old_x, $old_y);
    if($border) {
        $black = imagecolorallocate($new_img, 0, 0, 0);
        imagerectangle($new_img,0,0, $thumb_w, $thumb_h, $black);
    }
    if($base64) {
        ob_start();
        imagepng($new_img);
        $img = ob_get_contents();
        ob_end_clean();
        $return = base64_encode($img);
    } else {
        if(preg_match('/jpeg/i', $ext)) {
                imagejpeg($new_img, $newname);
            $return = true;
        } elseif( preg_match('/jpg/i', $ext)){
            imagejpeg($new_img, $newname);
            $return = true;
        } elseif(preg_match('/png/i', $ext)){
            imagepng($new_img, $newname);
            $return = true;
        } elseif(preg_match('/gif/i', $ext)) {
            imagegif($new_img, $newname);
            $return = true;
        }
    }
    imagedestroy($new_img);
    imagedestroy($img);
    return $return;
}

So, if you want to create a thumbnail, so that the thumbnail size will be base on smallest side, then do the following:

createthumb($targetFile_big,$targetFile, 170, 170);

In this case the smallest part will become 170px and the biggest proportionally bigger. Otherwise:

createthumb($targetFile_big,$targetFile, 170, 170, false);

In this case the biggest part will become 170px and the smallest proportionally less.

To make sure that this script works correctly, check that ImageMagic pack is installed on your Linux machine.

#! /bin/bash

dir=$1
target_dir=$2

mkdir -p $target_dir

list=`ls -1 $1`
for i in $list
do
        echo $i
        convert $dir/$i -resize 50% $target_dir/$i
done

Usage:

./convert_50.sh Pictures/temp/ Pictures/temp_new

This will resize all images in location Pictures/temp/ for 50% and will copy them to new location Pictures/temp_new