You can check for icon type with this snippet for JScript Panel.
var search_current_playlist = true; // if false, entire library is searched. foobar may become unresponsive with large collections - be patient.
var type = 3; // types: 0 front, 1 back, 2 disc, 3 icon, 4 artist
///////////////////////////////////////////////////////////////////////////////////
var types = ["front", "back", "disc", "icon", "artist"];
var items = search_current_playlist ? plman.GetPlaylistItems(plman.ActivePlaylist) : fb.GetLibraryItems();
var found_items = plman.GetPlaylistItems(-1);
for (var i = 0; i < items.Count; i++) {
if (utils.GetAlbumArtEmbedded(items.Item(i).Rawpath, type))
found_items.Add(items.Item(i));
}
if (found_items.Count > 0) {
plman.CreatePlaylist(plman.PlaylistCount, "Tracks with embedded art: " + types[type]);
plman.ActivePlaylist = plman.PlaylistCount - 1;
plman.InsertPlaylistItems(plman.ActivePlaylist, 0, found_items);
} else {
fb.ShowPopupMessage("None found.");
}