efind-gdkpixbuf is an extension for efind. It makes it possible to filter find results by image properties.
You need gdk-pixbuf2 to build this extension.
Returns image width.
$ efind . 'image_width()>=800'
Returns image height.
$ efind . 'image_height()>=image_width()'
Checks if image has an alpha channel.
$ efind . 'name="*.gif" and image_has_alpha()'
Gets the number of channels.
$ efind . 'image_bits_per_sample()>=2'