PhotoMesa is a free tool for managing image libraries. Dubbed a "zoomable image browser", it employs an innovative method for browsing a large number of images by zooming in and out of folders in a sort of "bird’s eye view". It also offers the ability to browse image collections by folder, category, people, year, and month, and for adding searchable tags and captions stored within the image files themselves using the IPTC standard.

This program was apparently developed based on research that was done in the University of Maryland’s Human-Computer Interaction Lab, and the end result is a very intuitive way of browsing image libraries. What you will immediately notice when you first start using this program is its unique (and quite pleasing) way of scrolling through a large number of images in "zoom mode" (I will attempt a description of this below, but if you want to get a sense of this see the video at the bottom of this review). Here are more notes on this program:

• Zoom mode: by default, Photomesa will scan the folders that you tell it to and generate groups of rectangles that represent your folder tree visually. What is nice about this representation is that (a) it serves to take maximum advantage of your available screen space, and (b) it allows you a bird’s-eye-view (or satellite-eye view more like) which allows you to easily browse your entire image collection in a very intuitive way.
• Scroll mode: is a normal interface of viewing folders or groups sequentially employed in most programs (such as Picasa). This is made available in case you prefer a conventional way of working with folders/groups. This is also a better interface when you need to see all images within folders, as zoom mode uses "representative" images for most folders until you zoom into it.
• Interacting with the program: the system of interaction under zoom mode is well thought out, and takes a very short time to get the hang of it. Left or right clicking over any rectangle zooms in and out of it, respectively. Each rectangle will only display a representative number of thumbnails, but once zoomed into will display all the images within using very small thumbnails (this depends on the program window size and the number of images within). Hovering on any thumbnail produces a larger floating preview of the image, which is very useful. You can perform operations on the images by selecting one or more images (using CTRL or Shift) and using a number of options in the context menu (rotating, captioning, making an image a "favorite", etc).
• Grouping and filtering: although the program segments folders (directories) into groups by default, it can group by any one or a combination of: category, people, years, months. These groups are available on the left hand pane and through a button on top of the main display. For example, you can group by category, then check "2007" in years and "December" in months to filter further.
• Sorting: regardless of how you group them, images in the main display can be sorted any number of ways, including chronologically by date, by title, by number of people or number of categories, by aspect ratio, etc.
• Metadada (categories and people): aside from years and months, which are self explanatory, the program uses "categories" and "people" as (which it terms "annotations") as metadata. The "people" tags allows you to tag your images based on the people that appear and them, while categories can be anything that you choose. The end result is that, for example, you can filter your images by those that, say, your friend Bob appears in during your skiing trip together (assuming "Bob" is defined as a people tag and "Skiing trip" is defined as a category, and the images properly tagged). Note that you can create sub-categories as well to further refine your filtering.
• Image filtering: you can designate images as "favorites", which will display a little star in their thumbnail(s), or otherwise designate images as hidden, which will remove them from normal view. You can also uncheck folders in the folder tree in order not to display their thumbnails (even when their contents are indexed in the PhotoMesa database). Altogether these tools hep make it relatively easy to work with precisely the images you want and remove clutter.
• Captions: you can add a (searchable) caption to any image simply by right clicking and typing one in.
• Searching: searches filenames, captions, annotations, folder names, and other available Metadata.
• Data storage: annotations (i.e. tags) and captions are stored within the image file itself in the photo header using a standard called IPTC, and backed up in an XML file within My Documents. PhotoMesa should be able to read metadata created with other programs that used the IPTC standard (such as ITag) and vice versa. The program also creates thumbnails and stores them in the installation directory.
• Supported image types: JPEG, GIF, PNG, BMP, EMF, ICON, TIF, WMF

Wish list

• Better support for panoramic images (one panoramic image I had would not open with Photomesa).
• A "properties" command in the context menu. I found I had a hard time identifying the image types for some images when working with them.

The verdict: even if you already use Picasa or another image management software you might want to try this. This program (a) is original and innovative, (b) introduces a very cool and interesting way to browse image collections, (c) allows for tagging image files using people and category tags, (d) allows for adding captions to images (e) stores metadata information in the image file itself, and (f) is free. Oh, and (g) is a definite Freewaregenius pick!

A video of PhotoMesa in action (note that the video seems to be of an earlier version of the program):

Version Tested: 3.1.2

Compatibility: WinAll. Requires Microsoft .NET framework 1.0 or 2.0. Get it here.

Go to the program page to download the latest version (approx 2.48 megs).