Laserfiche doesn't have a built-in way to search for images with certain dimensions, but you can use a direct SQL query of your repository's database. The "doc" table in a database for a LF repository contains one row per page. There are columns which store the width and height of any corresponding image file, in pixels. Please note that for a variety of reasons these columns might not be filled in correctly for all pages, but it's a good place to start.

Here's a sample query which will return all the entry IDs for documents which have an image page with a dimension that exceeds 16384:

SELECT DISTINCT t.tocid
FROM doc d JOIN toc t ON d.tocid = t.tocid
WHERE toc_flags & 2048 = 0 AND pagenum >= 0 AND img_size > 0
AND (img_width > 16384 OR img_height > 16384)