Regarding thumbnails, there is one very important thing to understand and it's best understood from the start.
The thumbnails displayed within the Lightroom preview when designing your index are not actually the thumbnails that will be used by your published index. They are standins only, used only as a point of reference so that you may design your page within the Web module's preview.
Published indexes will draw upon thumbnail images from within the image galleries themselves, and those thumbnail images will be sized according to the settings used to create that image gallery, not the sizes specified by the auto index design.
For easiest implementation, plan ahead. Know the size of your image gallery thumbnails, set your thumbnails to that same size when designing your auto index, and design your index accordingly. If you want larger, more iconic images to be used by your gallery index than actually appear in your image galleries, we can do that and will discuss it further on; but know that it will require additional steps in our publishing workflow.
Now, let's discuss the various options you have for displaying thumbnails in the auto index.
The default is that your auto index will randomly select a thumbnail image from each image gallery and display it on the index page. This is great because it's fully automatic, and works out very well with the Descriptive and Masonry index layouts.
If using TTG CE3 Horizon for your image galleries the random thumbnails work out well because the galleries don't actually display thumbnails, so you are free to export galleries with thumbnails however large you want them to appear in the index, rather than setting them to a size for gallery layout.
Because the random thumbnailing is completely automatic and hands-off, it's the easiest to use. To enable random thumbnailing, leave the Album Thumbnail field blank:
But random thumbnailing may not be appropriate for all layouts. For example, consider our 'Iconic' layout in which the album thumbnails are designed to be much larger than our gallery thumbnails:
Our gallery thumbnails are smaller than our auto index design, so this layout is probably undesirable. In this situation, we will want to use custom thumbnails. And we have two options for doing so.
In situations where it may be undesirable to have thumbnails selected at random, you may instruct the auto index to use a specific thumbnail. This may be a specific thumbnail from within the
/thumbnails/ folder, or a custom-made thumbnail that you've created separately from the gallery. There are lots of ways to create custom thumbnails, either cropping and exporting from Lightroom or creating them in Photoshop or some other application.
To use a specific thumbnail, supply the path to the thumbnail image relative to the gallery folder.
For example, to target a thumbnail within the gallery's
/thumbnails/ folder, we would write the path this way:
This gets filled into the Album Thumbnail field:
Here's a fun tip. If I plan to use custom thumbnails with a design, I will often fill in “thumbnail.jpg” as my Album Thumbnail, and will then save this as part of my template using the Template Browser. It looks like this:
Later, I export my gallery. In each of my gallery folders, I drop a custom thumbnail image named
thumbnail.jpg, like this:
Because I've saved the Album Thumbnail with my template, I never need to revisit the field again, and it's dead simple to add a thumbnail.jpg file to each of my image galleries as I export them. This works because the thumbnail image is always named the same, and always in the same place within each gallery folder.
It's also possible to create a folder containing several custom thumbnail images, and to have the auto index randomly select one of those thumbnails.
To specify a folder of custom thumbnails, supply the path relative to the location of the index. This folder may be inside the gallery folder (that's where I like to keep it), or in another folder. For example, here we have a
/custom-thumbnails/ folder inside one of our image galleries:
To instruct the auto index to select a thumbnail image from within this folder, we provide a relative path from the auto index location. In this example, that path would be:
Again, this goes into the Album Thumbnail field when creating our image gallery.
When using TTG CE3 Publisher to publish albums and album sets, thumbnail management is handled through the publisher interface for albums, and manually for album sets. This will be covered in greater detail in the TTG CE3 Publisher documentation.