problem with thumbnails

[reddwarf4ever]

when i create a video compilation i often use the user defined option to crop the edge off the video, however i dint realize that the uswer defined setting would be added to the thumbnails setting also, worse than that , the thumbnails refused to animate until i changed them ALL individually to letterbox

now all is ok

1 can this be sorted and have a default thumbnail setting e.g. letterbox....

thanks