I was wondering if there is a way to be able to search images based on orientation (horizontal or vertical images only)
actually i was thinking something based on the images dimension width and height, which already are in the metadata..
a script to compare which side is longer and bring results based on that . (width > height for vertical images and width < height for horizontal)
do you think something like that is possible ?
There are template functions available to check for landscape and you can do that via the object model. But as sbillard said it is not possible via the search itself. You would have to use the object model to note that somewhere via the custom field or even better a tag.
The current search engine does not handle expressions as I said above. However, if your images are uniform in size, say 600x800 you could search for "800" and enable the height field. That would return all images that are 800 high.
If you images vary in size but have a small set of possibilities that do not overlap width with height values you can have multiple matches by using the OR function in the search.
Otherwise what you want is not possible nor even very likely to be implementable withing the current structure.