sam l

Hi Petra,

Thanks so much for your quick reply. This is the best support team I’ve ever met here!

So I solved the problem with No.2 suggestion, to install the ‘Regenerate Thumbnails’ plugin.
After that, found some of thumbnails which I edited before were not generated. I had to remove one by one to let it ran automatically, then re-edited again (Luckily only few of them are being edited manually)

I guess I turned off the plugin “Post thumbnail editor”, which caused the problem.(not sure)

Anyway, I have to say thanks again for your kind help. The detail info really helped a lot!