As per the title of this issue, the icon for a database_field is only displayed if it is in the /mod/data/pix/field folder. But since this is outside of the plugin structure, it won't be installed there with the plugin. It leaves an ugly broken image link on the page, and everyone blames the plugin dev.

I suppose I could copy the icon to the correct folder using an install.php script, but it seems kind of wrong. It would be much nicer if the custom plugin icons were detected and displayed as are other subplugins.