So when I moved to ubuntu the one thing I lost was my favourite photo gallery program for windows. To be fair, it hadn't really been a complete solution anyway, so I decided to write a command line script (which uses php and imagemagick) to create a gallery for me. It creates thumbnails and 'web sized' images, and then makes an index file to show them all with links to the 'web sized' images. 
#!/usr/bin/php
<?php

// First, some configuration variables:
$thumb_max_width = '150';
$web_ready_max_width = '1000';
$gallery_dir_name = "gallery";
$ThumbPrefix = "thumb_";
$WebReadyPrefix = "";
$GalleryFileName = "index.html";

// We could define the header and the footer in another file, then include them. But whatever
$htmlfileheader = "<html><head><title></title></head>\n";
$htmlfileheader .= "<body>\n";

$htmlfilefooter = "</body></html>";

// we should use the current dir for input, a subdir for output,
// and a sub/sub dir for the images?
// do we want to output html files for each image?
// for the first round, one html file, outputs
// links to each (large-ish) image, and an overall
// html file that we configure to have all the links and thumbs

function makeThumb($image, $DestDir, $max_width, $prefix)
	{
	// Made with the help of http://sniptools.com/vault/dynamic-thumbnailing-with-imagemagick-in-php

	$thumbFileName = $prefix.$image;
	// do something to make a little file

	// Specify your file details
	$current_file = $image;

	// Get the current info on the file
	$current_size = getimagesize($current_file);
	$current_img_width = $current_size[0];
	$current_img_height = $current_size[1];
	$image_base = explode('.', $current_file);

	// This part gets the new thumbnail name
	$image_basename = $image_base[0];
	$image_ext = $image_base[1];
	$thumb_name = $DestDir."/". $prefix.$image_basename.'.'.$image_ext;

	// Determine if the image actually needs to be resized
	// and if it does, get the new height for it
	if ($current_img_width > $max_width)
	{
	  $too_big_diff_ratio = $current_img_width/$max_width;
	  $new_img_width = $max_width;
	  $new_img_height = round($current_img_height/$too_big_diff_ratio);
	  // Convert the file
	  $make_magick = system("convert -geometry $new_img_width"."x"."$new_img_height $current_file $thumb_name", $retval);
	  // Did it work?
	  if (!($retval)) {
	    echo 'Thumbnail created: <img src="' .$thumb_name .'">';
	  }
	  else {
	    echo 'Error: Please try again.';
	  }
	}
	else
	{
	  echo 'No need to resize.';
	}

	return $thumbFileName;
	}


function getimages($CurrentDir)
	{
	// return an array of image files

	//using the opendir function
	$dir_handle = @opendir($CurrentDir) or die("Unable to open $path");

	echo "Directory Listing of $CurrentDir";

	$ArrayCounter=0;

	//running the while loop
	while ($file = readdir($dir_handle)) 
	{
		$ext = substr($file, strrpos($file, '.') + 1);
		echo "$file has extension $ext";
		if (($ext=="jpg")||($ext=="JPG"))
			{
			echo "match!";
			$ImageArray[$ArrayCounter]=$file;
			$ArrayCounter++;
			}
		echo "\n";
	}

	//closing the directory
	closedir($dir_handle);

	return $ImageArray;

	}



// Since this is a command line script, we'll include some nice helpful stuff
if ($argc != 2 || in_array($argv[1], array('--help', '-help', '-h', '-?'))) {

	echo "This is a command line PHP script with one option.

	  Usage:
	  $argv[0] <directory full of images>

	  <directory full of images> contains the images
	  you want to make an image gallery from.
	  With the --help, -help, -h, or -? options,
	  you can get this help.
	  \n";
	}
else
	{
	echo "creating gallery from files located in $argv[1]";

	$FromDir = $argv[1];
	if ($FromDir==".")
		{ $FromDir = getcwd(); }
	echo "From Dir is $FromDir";

	$destDir = "$FromDir/$gallery_dir_name";
	// $ThumbDir = "$CurrentDir/gallery/thumb"; I think I'll put
	// everything in one dir
	$workDir = "/var/tmp"; // define this as per local system

	$GalleryFileName = "$destDir/$GalleryFileName";

	// make the dir the thumbs will go in
	$mode="0750"; //permissions
	$output=mkdir($destDir);
	echo "I made a dir is ".$output."\n";

	echo "\n$CurrentDir - $destDir - $workDir";

	# fetch image details
	$images = getImages($FromDir);

	echo "\n----\n";

	$GalleryFile = fopen($GalleryFileName, 'w') or die("can't open file");
	fwrite($GalleryFile, $htmlfileheader);


	# display on page
	foreach($images as $img) 
		{ 
		// This is where the magic happens
		// TODO: create an HTML file for each image, allow facebook share?

		// make the thumb
		$ThumbFile = makeThumb($img,$destDir,$thumb_max_width,$ThumbPrefix);
		// make the web friendly large image
		$ImageFile = makeThumb($img,$destDir,$web_ready_max_width,$WebReadyPrefix);
	
		fwrite($GalleryFile, "<a href=\"$ImageFile\"><img src=\"$ThumbFile\"></a>\n");
		}

	// Clean up - write the footer and close the file
	fwrite($GalleryFile, $htmlfilefooter);
	fclose($GalleryFile);
	} // End of the 'else' statement which begins the actual program
?>