I personally have disabled the thumbnail creation on my system as I see it more of a way to leak private information. Anyone with access can look at the contents of thumbs.db files to check out what a user has been looking at in the past. This may even work if the images used to generate the thumbnails are long gone.

Thumbcache Viewer is a new portable Open Source program for Windows to display the contents of a thumbcache_*.db file. The developer has created a command line and graphical user interface version which need to be downloaded separately.

The first thing that you need to do after starting the program is to click on File > Open to load a file browser to locate and load a thumbcache_*.db file from a connected storage device.These files are located only on Vista and Windows 7 systems, and located in the following folder: %homedrive%\Users\%username%\AppData\Local\Microsoft\Windows\Explorer

Please note that you may need to disable the preference to hide important operating system files automatically on the system to see the thumbs.db files in that file browser. The program displays the files, filenames, sizes, checksum and hash information in its interface.

The selection of an entry in the database displays the thumbnail image in a small viewer window. You can move around with the mouse or arrow keys and scale the image with the + or – keys to zoom in or out of the thumbnail image. Alternatively, you can use the mouse wheel to zoom in or out as well.

Files can be renamed by clicking again on the selected thumbnail in the table. Just enter a different file name and press enter to complete the process and save the new file name.

You can download the latest version of Thumbcache Viewer from the Google Code project site. Windows XP users can alternatively Thumbs.db viewer and cleaner which I reviewed back in 2007.

Here is a screenshot of the thumbnail preview mode in Windows Explorer.

As you can see, supported image formats are displayed with their thumbnails in Windows Explorer. Now look at the following screenshot that shows the same folder on the system after disabling image previews in Windows Explorer.

Before I’m going to demonstrate how to disable and re-enable thumbnail previews in Windows Explorer, I’m showing you how to change the view mode. Most Ghacks regulars know how to do this, but there may be some users who would like to know how to make that change.

You can click on the view mode icon in Windows Explorer to change the view mode of the current folder. A click on the icon itself allows you to flip through all available view modes, a click on the down arrow displays them all for selection in list form.

You can change the setting when you are in Windows Explorer. You can alternatively click on the Start Menu and then on Computer to open the Windows Explorer menu. Click the Organize link and there on Folder and Search Options.

Switch to the View tab in the configuration window that opens up and put a mark into the Always show icons, never thumbnails option in Windows Explorer.

The changes take effect immediately, and images that have been shown as previews are now shown with their icons instead. Removing the check mark from the setting will revert the changes. (via)

For example, many posts benefit from a nice, clean thumbnail seated just to the left of the title of your posts. Such images break up otherwise monotonous, similar posts into individual units with their own appearance and characteristics. They can make the difference between an unattractive blog blanketed in text and an interesting web magazine with illustrations.

To implement these thumbnails you need to tell WordPress to look for the specific images you want and then to add them itself. You can do this by creating a field in each post called customimage which, when found, will tell WordPress to make the image appear. On the off chance that you do not add the customimage field to a particular post, you want WordPress to instead display a default image.

To begin, select an image that you would like posts to display by default. This could be your face, your dog, a speeding car – really, it’s completely up to you. Open the image in your favorite editor (Gimp, Paint.net or any other image editor that you may have at your disposal) and set it to whatever pixel dimensions you prefer. Be mindful that regardless of how long your blog title is, your photo will always be the same size. Somewhere between 150 by 150 and 250 by 250 pixels is probably a safe bet, and square boxes are easier to place various images in later, as opposed to rectangular ones. Once you have a nice image name it something you can remember (standard.gif, default.gif, etc.).

Next, upload the default image into your theme’s image directory. This makes it available to all pages of your site and any post missing the customimage field.

Now for the important part: post the following code into the index.php file of your WordPress wherever you would like the thumbnails to appear:

<?php $postimageurl = get_post_meta($post->ID, 'customimage', true);

if ($postimageurl) {

?>

<a href="<?php the_permalink(); ?>" rel="bookmark"><img src="<?php echo $postimageurl; ?>" alt="Post Pic" width="200" height="200" /></a>

<?php } else { ?>

<a href="<?php the_permalink(); ?>" rel="bookmark"><img src="<?php bloginfo('template_url'); ?>/images/yourwebsite.gif" alt="Screenshot" width="200" height="200" /></a>

After you are finished copying over the code and pasting it in index.php, save the file. Your posts will now place whatever image you chose as your default (customimage) earlier beside each entry. That’s good, but you really want to be able to change that image – the point of this entire exercise is to make each post different.

All that you need to do is create a custom field with each entry called customimage (not in italics, of course). Change the value each time to the URL of whatever image you would like to display beside the particular post and you will be set to go. Enjoy having a unique thumbnail beside each post, unless you allow it to fall to the default.

Images clearly make for a more attractive blog post for the majority of readers. Are you one of those? Photos attract, so make sure that you blog is attractive and attracting.

Update from Martin:

You do not necessarily have to paste the code into index.php. You can alternatively paste it into single.php for individual posts, category.php for categories or tags.php for tags.

If you are not familiar with web development you may want to select a theme that supports post thumbnails out of the box. There are even some that take the first image of each post automatically and use it as the post thumbnail provided that you have not added a thumbnail image of your own to the post.

You also need to consider that images will increase the loading time of the site. If you have a slow loading site, it is probably best not to add more images to the blog, or at least not before you started to optimize the blog code for speed.

Programs like Auto Movie Thumbnailer automate the creation of video thumbnails as much as possible. The free software program offers lots of features to customize the thumbnail generation.

Users who want quick results can keep the standard settings to speed up the process. It takes only three steps to create thumbnails of videos stored on a local or network drive.

It starts with the selection of one or multiple directories containing video files, continues

It begins by selecting a directory that contains the movies, continues with the the output directory and ends with a click on the start processing button to process all videos in the selected folders.

movie thumbs

The processing time depends largely on the amount of videos stored in the selected directories, their length and the computer’s processing powers.

The preview window displays scenes from each video, the log the outputs. Auto Movie Thumbnailer makes use of Mplayer to create the thumbnails.

One oft he biggest strengths of the program is its customizability. It is for instance possible to configure the number of thumbnails based on a video’s file size, the supported video types, color and design settings of the thumbnail image or Mplayer command line arguments to fine tune the output.

movie thumbnails

A single video thumbnail image looks like this:

movie thumbnail example

The only difficulty that some users may experience is that it is not possible to select a single file for thumbnail creation. The best way to create thumbs for one movie is to create a new directory, move the video file into that dir to process it afterwards in the program.

Auto Movie Thumbnailer provides all the necessary options to create thumbnails from a video collection. The program is compatible with 32-bit and 64-bit editions of the Windows operating system.

The option to disable the caching of thumbnails and thus the generation of thumbs.db files is available by following this path: User Configuration > Administrative Templates > Windows Components > Windows Explorer. The entry “Turn off the caching of thumbnails in hidden thumbs.db files” is not configured by default. Enabling that policy will prevent that thumbs.db files are created.

This does not delete the thumbs.db files that are already stored on the computer system. That’s where the software Thumbs.db Cleaner comes in handy. It can be used to crawl a hard drive or specific directory for thumbs.db instances. All files that are found will be displayed in a list with information like the file size, data of creation or modification and file path.

Checkboxes are used to mark files for the cleanup process with all entries selected by default. A click on the Clean button will remove all selected thumbs.db files from the computer system. Thumbs.db cleaner is a portable Open Source application for the Windows operating system that can clean thumbs.db files effectively from a computer system. Ideal for a sweep after disabling the automatic generation of thumbs.db entries in Windows. (via JKWebtalks)

Sadly, there is no publicly available codec for the Photoshop PSD format but the newly released Microsoft Expression Blend 3 design tool (which, by the way, is nothing short of amazing for WPF and Silverlight design) includes such a codec so installing Blend 3 automatically installs the PSD codec. For those who don’t have a need for Blend and don’t want to install it, here is a little hacking guide to extract the codec (a 256KB dll) and use it separately:

Get the codec and its dependencies:

Download Microsoft Expression Blend 3.0 (3.0.1927.0 7/20/2009) Trial: Link
Using 7-Zip, open ‘Blend_Trial_en.exe’ from step (1) and in the ‘Setup’ subfolder, open ‘BlImp.cab’ then extract ‘PSDCodec.dll’
Download the Visual C++ 2008 SP1 Redistributable Package (x86): Link

Codec installation:

Install the VC++ Runtime by running vcredist_x86.exe from step (3) above.
Copy PSDCodec.dll from step (2) to some location on the harddisk, e.g. “C:\Program Files\PSDCodec”
Register the codec from an administrator’s command prompt by running the following command: regsvr32 “C:\Program Files\PSDCodec\PSDCodec.dll”

That’s it, Windows Vista Explorer should soon begin to display thumbnails for all PSD files that were saved from Photoshop with the “Maximum Compatibility” option. As a side effect, WIC-aware image viewers such as FastPictureViewer Professional (http://www.fastpictureviewer.com) automatically benefit from the codec installation and uses it to open and display the same PSD files with full fidelity.

One interesting application for that purpose is RightThumb for the Windows operating system. It is a portable application that can be integrated into the Windows Explorer context menu to offer the option to create a thumbnail from selected images.

Several parameters of the thumbnail creation can be configured upon startup including the output format for the thumbnail image, the maximum dimension for the image, the quality of jpg images, compression of png images, the resample filter and if desired a prefix identifier for the image. The image will be automatically sharpened after resizing and it is possible to select a different output folder for the thumbnail image.

The program can be closed after the initial configuration and is from then on accessible from the Windows context menu if that option has been selected. Right Thumb (via Barry’s Computer Tips) is a free download for the windows operating system.

The system works by assigning thumbnail icons to every image in the active folder which are then available independently of the view mode that the user has selected for the folder. When I read about the thumbnail image generator I had fears that it would slow down the system but this is apparently not the case since the application only becomes active when a user opens a folder that contains images.

Image icons are stored in a thumbnail cache that is set to keep 2000 thumbnail images with a size of 31 Megabytes. The size of the image icons cache can be changed, the maximum is 10000 thumbnails with a size of 156 Megabytes.

The cache can be cleared or disabled in the settings as well. They also contain the option to disable thumbnail generation. The settings can be accessed from the Windows Control Panel which is a bit unusual.

The program can be uninstalled easily which will also clear the icon cache leaving no traces of the application on the system. The application is compatible with Windows 98, ME, 2000 and Windows XP and supports the most popular image formats (JPG, JPE, JPEG, JP2, J2K, GIF, PNG, BMP, WBMP, EMF, WMF, PCX, PBM, PGM, PNM, PPM, RAS, TIF, TIFF, and TGA.)

This can be checked easily by trying to play the video with Windows Media Player or any other media player that does not use binary codecs. Five output sets are available that define all sorts of parameters like the number of thumbnails per row, the background color and the width and / or height of the thumbnails.

Everything in there can be changed and there is much to explore including several options that I have not mentioned.

Several videos can be added to the program queue by either selecting a folder or files from the system. Two output settings exist. The first creates an image for every thumbnail while the second combines all thumbnails into an image.

The creation process itself is fast and works flawlessly as long as a supported codec is installed. I ran into a bit of problems with several video files because I use SMPlayer as my main video player which uses binary codecs that other applications cannot use. This meant that I received quite a few “failed” messages because of missing codecs.

Installing the codec would naturally resolve the problem.

Each image is represented as a jpg image in the thumbs.db file which makes it relatively easy to extract those images again. The thumbnails are stored in a centralized location in Windows Vista with the name thumbcache_xxx.db where xxx is a number between 1 and 999. That folder is located at %sysroot%\Users\Owner\AppData\Local\Microsoft\Windows\Explorer.

A flexible small tool that can extract all images from thumbs.db files is Thumbs Extract. It’s a command line utility and the command is ThumbsExtract.exe path to thumbs.db, for example ThumbsExtract.exe c:\thumbs.db if the file is located on the c:\ drive.

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer

Select Edit – New – Dword Value and name it ThumbnailSize. Double-click the new entry and select decimal and a number between 32 and 256. The default value for the thumbnail size is 100, if you would like a bigger size increase the number above 100, if you like smaller ones choose one below 100.

The new settings will become active after you restart your system.