In the image below, you can see an example of a label filter that is
used to override icons for particular files. A label has been created (called
HD Image) that defines a custom icon. A label filter has also
been created that matches JPG files (it could be used to match more filetypes
if desired) with a height of at least 1080 pixels. You can see in the Lister
image at the bottom that the high resolution images are displayed with the
custom icon, whereas the smaller images have the standard JPG icon.