Thumbnail Cropping Utility


AutoGallery SQL includes a web based thumbnail cropping utility that can be used by both gallery submitters and yourself as the TGP administrator. The cropping utility requires that your server have the ImageMagick Perl module installed. If your server does not have ImageMagick, you will only be able to upload pre-created thumbnails. This document will describe how to use the thumbnail cropping utility.

Browser Requirements

The thumbnail cropping utility makes extensive use of JavaScript and DHTML, and therefore you will need a modern web browser. Currently the following web browsers are supported:

Internet Explorer 6+
Mozilla 1.6+
Firefox 0.9+

You will also need to make sure that your browser settings allow for execution of all JavaScript, and that you are allowing pop-up windows at least for the domain where AutoGallery SQL is installed.

The Thumbnail Cropping Interface

Through the control panel you can access the thumbnail cropping interface from the Display Galleries interface by clicking on either the [No Thumb] or [Edit] links in the Display Galleries interface for submitted galleries or the Manage Galleries interface for permanent galleries. This will cause a pop-up window to appear with the thumbnail cropping interface. For gallery submitters, the thumbnail cropping interface will be automatically displayed if they select the 'Select and crop an image from your gallery' option for the Preview Thumb field. The basic layout of the thumbnail cropping utility is shown below.

Each of the labeled items is described below.
  1. This shows all of the thumbnails that you can select from. Clicking on one of these thumbnails will cause the full sized image to load in the section labeled B. You can use the scrollbar to see more images.
  2. When the cropping page is first loaded this section will be empty. After you click on one of the thumbnails, the full sized image will be loaded in this area. Once it is loaded you can click and drag your mouse over the image to select the area you want to crop.
  3. This is a realtime preview of the area of the image that will be cropped and it's size. Note that this is a simple preview and does not represent the final quality of the generated thumbnail. Additionally, adjusting the brightness and contrast will not be displayed in the preview thumbnail.
  4. It is possible to adjust both the brightness and contrast of the created thumbnail. For the contrast you can either leave it the same (=), increase the contrast (+) or decrease the contrast (-). For the brightness you can enter a positive value greater than zero to increase the brightness or a negative value to decrease the brightness.
Once you have selected the area of the image that you want to crop and set the brightness and contrast settings how you want them, you can double click inside the selection that you have made on the image. The software will then use ImageMagick to crop the thumbnail as you have specified.