In Cover Grid if I edit a cover (I used IrfanView via Open With) then there's no obvious way to get the thumbnail to refresh, it still shows the image thumb prior to edit, tried Resize, went into Book List, I can see the edited cover in Book Details, Edit Metadata, Cover Browser and Book Information.
If
Edit Metadata->Trim is used on the edited cover the thumb is refreshed - as I said - no obvious way. Also obvious is that if I edit the cover with an image editor then how does Calibre know I did that. I can live with the Trim, but lets say someone edited the cover to add a border would Trim take it away.
Sometimes Page Down does not show last couple of rows of thumbs, Down Arrow also doesn't work in this situation - must move the slider with mouse or roll mouse wheel to see last couple of rows - or press Ctrl/End
BR