Combining Image module with custom made module...

Hi everyone,
I am writing my custom module that requires a user to upload a high res-image, convert the image to a thumbnail, and then display it in the node. With the displayed image, if a user hovers over the thumbnail it creates a zoomed in version of the high resolution image.

I am learning module development and need help as to how to successfully upload an image and display it on the page, drawing from image module. As far as I know, there is a function called image_create_node_from(). The snippet from image module is as follows:

function image_create_node_from($filepath, $title = NULL, $body = '', $taxonomy = NULL) {
  global $user;

  if (!user_access('create images')) {
    return FALSE;
  }

  // Ensure it's a valid image.
  if (!$image_info = image_get_info($filepath)) {
    return FALSE;
  }

  // Make sure we can copy the file into our temp directory.
  $original_path = $filepath;
  if (!file_copy($filepath, _image_filename($filepath, IMAGE_ORIGINAL, TRUE))) {
    return FALSE;
  }

  // Resize the original image.
  $aspect_ratio = $image_info['height'] / $image_info['width'];
  $size = image_get_sizes(IMAGE_ORIGINAL, $aspect_ratio);
  if (!empty($size['width']) && !empty($size['height'])) {
    image_scale($filepath, $filepath, $size['width'], $size['height']);
  }

  // Build the node.
  $node = new stdClass();
  $node->type = 'image';
  $node->uid = $user->uid;
  $node->name = $user->name;
  $node->title = isset($title) ? $title : basename($filepath);
  $node->body = $body;

  // Set the node's defaults... (copied this from node and comment.module)
  $node_options = variable_get('node_options_'. $node->type, array('status', 'promote'));
  $node->status = in_array('status', $node_options);
  $node->promote = in_array('promote', $node_options);
  if (module_exists('comment')) {
    $node->comment = variable_get("comment_$node->type", COMMENT_NODE_READ_WRITE);
  }
  if (module_exists('taxonomy')) {
    $node->taxonomy = $taxonomy;
  }

  $node->new_file = TRUE;
  $node->images[IMAGE_ORIGINAL] = $filepath;

  // Save the node.
  $node = node_submit($node);
  node_save($node);

  // Remove the original image now that the import has completed.
  file_delete($original_path);

  return $node;
}

Problem is, how do i use it?? Where in my module, called imagezoom, should I call it? Any help GREATLY appreciated!