Thumbnail Image Viewer

The Witzend Thumbnail Image Viewer ActiveX control accurately displays miniature thumbnail renderings of graphics files. Thumbnail views are adjustable to any dimension, from postage-stamp size to full-screen.


The Witzend Thumbnail Image Viewer gives your applications the ability to accurately render graphics images in a window of any size, faithfully reflecting how the image would appear when shown at its normal size. Your application simply provides a path to the graphics file, and the Thumbnail Image Viewer does the rest. The Thumbnail Image Viewer recognizes and displays all of these common image formats:

  • BMP (bitmap), ICO (icon), CUR (cursor)
  • WMF (Windows metafile), EMF (enhanced metafile)

Files can be located virtually anywhere — a local hard drive, a network server, or on the World Wide Web.
The screen shot to the left conveys better than anything we can say here what the Thumbnail Image Viewer is all about. It gives your application “the whole picture”, able to convey instantly a quick idea of what a graphics file looks like with maximum convenience for your users.

Test Drive the Thumbnail Image Viewer

You can take the Thumbnail Image Viewer for a test drive using our free image viewer utilities. Try them both!

WitzImg Demo

The WitzImg demonstration program lets you browse for graphics files, and then displays a thumbnail image of each selected file. Click here to download the utility’s installation program, named Setup3:

Download the Image Viewer Utility (400K)

The Setup3 program installs the Thumbnail Image Viewer on your system and runs the WitzImg viewer utility. The Setup package includes an Uninstall feature. We hope you will find the WitzImg utility so handy you will want to keep it, but otherwise you can completely restore your system to its former configuration. Uninstall the WitzImg package through Add/Remove Programs in Control Panel.


The SlideShow utility demonstrates how an application can use the Thumbnail Image Viewer to display multiple image files as a slideshow. Simply browse to a folder that contains graphics files and SlideShow shows them as a series of thumbnail views. SlideShow is an elegant program, yet its first version was written in less than an hour! (That’s the beauty of component software.) The program is coded in Visual Basic, and is one of the example projects that come with the Thumbnail Image Viewer.

Download the SlideShow Viewer Utility (39K)

Run the Setup3 program described above before running SlideShow. This is because Setup3 installs the Thumbnail Image Viewer ActiveX control, which SlideShow uses to display slides.

Technical Specifications

Written entirely in C++, the Witzend Thumbnail Image Viewer is an ActiveX control only 240K in size. As is proper for component software, the Thumbnail Image Viewer runs without the need for auxiliary library files such as Microsoft Foundation Library (MFC) or Active Template Library (ATL). This independence ensures fast load times. It also makes installation bullet-proof, an important consideration when distributing the Thumbnail Image Viewer with your applications.


Designed for simplicity, the control exposes only fourteen properties that govern how an image appears in its view window. For example, the Fit property determines which of three sizing options the Viewer uses when rendering an image:

  • Auto-fit — The image appears in its entirety, squeezed into the confines of the view window. The view window can be any size determined by the client program.

  • Actual size — The image appears in its full dimensions and is not sized to fit inside the view window. Images smaller than the window appear completely, either centered in the window or at the upper right corner.

  • Maintain Aspect — This option is much like auto-fit, except that the Thumbnail Image Viewer considers the image’s aspect ratio when sizing, ensuring that round circles appear round and square boxes appear square in the thumbnail view.

Other properties include Center, which governs whether an image is centered inside the view window. The Frame property causes the Thumbnail Viewer to enclose the image in an attractive frame. The Logo property lets your application specify an image to display in lieu of a selected file. This graphic can be a company logo, a message, decoration, or any other design you wish.


Four methods, Refresh, Erase, Rotate, and Close give the host program additional control over the display. Their names indicate what the methods do. Rotate can turn an image to any angle from 0 to 359 degrees. (The option is available only under Windows NT and higher. Calling Rotate under Windows 95 or 98 does no harm, but the method ignores the call.)

A note about file locations — The Witzend Thumbnail Image Viewer can read image files from disk or off the Web. The client application simply provides a file path or URL address specifying a location, and the Thumbnail Image Viewer automatically retrieves, parses, and displays the file.


The Thumbnail Image Viewer component provides extensive support for drag-and-drop, recognizing dropped content from various sources:

  • Files — An image file can be dragged from any Windows Explorer source. The Thumbnail Image Viewer takes care of all the details of locating and rendering the image.

  • HTML — The Thumbnail Image Viewer recognizes drops from any HTML source. For instance, the user can drag an image from a browser window and drop it onto the Viewer, where it can be rotated and resized.

  • Text — Text drops, which might be a file path or URL, can be from any text source that supports drag-and-drop, such as a word processor.

The Thumbnail Image Viewer fires COM events to keep the container application informed of drop activity as it occurs. Your application can optionally receive notifications when a drag is detected, when a drop occurs, and when the cursor leaves the Viewer window.

Color mode

The Thumbnail Image Viewer recognizes 256-color mode, and intelligently manages palettes as required when displaying images. The host program can even specify its own palette.


The Thumbnail Image Viewer uses apartment threading, making access very efficient for multi-threaded applications.


The Thumbnail Image Viewer ActiveX control is available for a one-time license fee of $49.95 US, which includes:

  • 30-day warranty
  • Free technical support throughout the warranty period
  • Complete on-line documentation
  • Example source code for typical C++, Visual Basic, and Web-based projects

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Overlaying Thumbnail Images