If the Icons are too big in recoll simply replace them in this folder:
/usr/share/recoll/images
(access this folder with root privileges)

In order to make the result list look much, much nicer and easier to read you can also add this html-code.
Go to Settings -> GUI Settings -> Result list tab -> "Edit Format String for Results paragraph" and paste the following source code there, which you can find in the readme.txt file that comes with this download.