Image thumbnails are those small-size images that represent your photos but do not occupy a large space on the screen. Thumbnails have a visual appeal to your visitors, over using text lists. People can quickly see any photo items of interest to them, so this enhances their experience visiting your site.
Adding thumbnails is easy to do at the same time you are adding the media to TNG. See the Wiki page at Media – Images for more information.
But perhaps you have to regenerate thumbnail images on your site, for whatever reason. TNG has a handy tool for that purpose. Most likely, if you are using TNG as a backup to your home computer family tree, and importing GEDCOM data, you will need to generate thumbnail images and thumbnail links for any new images.
Log in, then go to Administration >> Media, and click on the Thumbnails tab. The next page has two sections: Generate Thumbnails and Assign Default Photos.
Clicking on the Generate button will go through all of your images, JPG, GIF and PNG files, and create a thumbnail copy, if one does not already exist.
The thumbnail image file will be created in the same subfolder as the image itself. TNG will add a prefix (or suffix) to the filename. By default, it is “thumb_”, but you can change that in Setup >> General Settings >> Media if you wish.
If necessary, you can regenerate fresh thumbnails on all of your images, using the first checkbox.
If you suspect that some images are still not showing a thumbnail, the problem might be with a missing or incorrect file pathname. Use the second checkbox to have TNG re-evaluate thumbnail pathnames and to then recreate correct paths. Otherwise, the Generate button could be regenerating invalid thumbnail names.
Assign Default Photos
When you add or edit a person, you have the opportunity to assign a default photo (actually, a thumbnail image) to that individual’s profile page, pedigree charts and family group sheets.
You can add default thumbnails, individually, manually, by going to a person’s profile page, then following the steps illustrated, below. Click on the Choose default photo, select a photo, which will add the thumbnail to that profile page. Before saving, check on the media edit page, Media Links, that you have the photo linked to the right person, that you have created a thumbnail image and that the Default Photo box is checked. That should put the thumbnail on the individual’s profile page.
There is something satisfying in going through the old photos and selecting an attractive sepia image to be featured on the profile page for that ancestor.
If you need to set up profile thumbnails in bulk, then on the Media >> Thumbnails page, click on the Assign Defaults button to have TNG go through all individuals, families, sources and repositories of the selected tree and assign the first photo for that person to be the Default Photo. If you check the “Overwrite existing defaults” box, then TNG will override any previous selection.
This article can be found on the Wiki tutorial site at: Media – Images “Creating image thumbnails”.