Image indexing

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Image files (JPG, GIF, PNG and TIFF) can be searched for and indexed by Zoom using our ImageInfo plugin. Note that plugin support is not available in the Free Edition.

With the image plugin installed and enabled, you will be able to search for image files by:

Meta information such as title, description, author, etc. which is stored within the image files.
Technical data stored in the image file (eg. camera make or model, shutter speed, flash setting, etc.) - see "Searching for technical information"
Filename of the image files (provided you have Filename enabled in "Indexing options")
Text that is used in any direct links to the image file
ALT text used to describe the image on the web page (provided you have ALT text enabled in "Indexing options")

Enabling image search

To enable image search, you will need to install the image plugin and add the necessary file extensions to your "Scan Options" in the Configuration window. For more information, please refer to "Installing a plugin" and "Using the plugins".

Enabling thumbnails

You can also setup thumbnail previews of each image to be displayed alongside each search result. See "Icons and thumbnails" for more information on how to achieve this.

Improving image search accuracy

As mentioned above, the image searching capability in Zoom depends on the accuracy of the text used to describe the image, and the meta information which has been assigned to the image.

To improve your image searching accuracy, you should make sure that you have meaningful text in the abovementioned places. For example, the following would be a poor use of the ALT text to describe the image:

<img src="th_pangkor_beach.jpg" alt="a screenshot">

 

This would mean the image would only be found by searches for the word "screenshot" which is hardly helpful or representative. A more meaningful use of ALT text would be:

<img src="th_pangkor_beach.jpg" alt="Pangkor beach in Malaysia">

 

This would allow the image to be found by searches of the word "pangkor", "beach" and "malaysia".

Similarly, if you have text links to your images like so:

<a href="pangkor_beach.jpg">This</a> is a picture of pangkor beach.

 
Zoom would only associate the word "this" with the image, which is again, less than useful. A more meaningful link would be like so:

<a href="pangkor_beach.jpg">A picture of pangkor beach</a>
 

But of course, the best way to ensure good image searching is to populate the meta information within your image files with correct and meaningful information.

Editing meta information for my images

There are several ways you can edit the meta information in your image files. The easiest way is to do so from Windows Explorer, by right-clicking on the image and selecting "Properties". Here, under the "Summary" tab, you can specify the "Title", "Subject", "Author", and add "Keywords" and "Comments".

There are also third party applications which allow you to specify more information (or add meta data to a number of files in one go). Note that with these other applications, there are additional fields available, but Zoom will only index the abovementioned fields.

For more information and examples on editing meta information, please see our FAQ page here:
http://www.wrensoft.com/zoom/support/faq_plugins_image.html

Skipping small image files

By enabling image indexing, you may end up indexing a large number of tiny images used for positioning or as layout tools (eg. little arrow images, text images, boxes and backgrounds). To avoid this, you can configure Zoom to only index images which are larger than a certain file size, effectively skipping small images which are unlikely to be meaningful.

To do this, double-click on the image file extension (on the "Scan options" tab of the Configuration window) and change the value in the setting labelled "Only index images larger than x kilobytes". The default value is 5 kilobytes.

Alternatively, you can skip image files by filename or path via the "Skip options" tab of the Configuration window, as you would to skip any other files from indexing.

Searching for technical information

Some image file formats contain various technical information regarding the image's dimensions, camera type, etc. which you can search by. The following is a table listing the various technical data available for each of the image formats supported.

 

Image file format

Example

JPEG

PNG

TIFF

GIF

Meta information

Author

Y

Y

Y

N

John Smith

Description

Y

Y

Y

N

Photo of a beach

Title

Y

Y

Y

N

Pangkor Island, Malaysia

Keywords/Comments

Y

Y

Y

N

beach, sun, sand, vacation

Technical information

Width

Y

Y

Y

Y

800

Height

Y

Y

Y

Y

600

Make

Y

Y

Y

N

SONY

Model

Y

N

Y

N

Cybershot

ExposureProgram

Y

N

Y

N

manual control

FNumber

Y

N

Y

N

F2.8

Aperture

Y

N

Y

N

F2.8

ShutterSpeed

Y

N

Y

N

2.5

ExposureTime

Y

N

Y

N

1/100

Flash

Y

N

Y

N

fired

DateTaken

Y

Y

Y

N

2005-11-07 13-48-01

These fields of information are indexed in the format of <type>:<value>

In order to search for a specific field, you should enable Colon character as a word join character in the "Indexing Options" tab of the configuration window. This would allow you to search for words containing a colon character as required for these fields.

You can then search for specific fields on your search page, for example, to search for images with a width of 500 and a shutter speed of 2.5, you would enter the following into your search box:

width:500 shutterspeed:2.5

 
You can combine theses searches with your normal search terms, as well as using wildcard characters ("*" and "?") to narrow your searches down further.