juner

Thank you so much, tdsm.
I’ve tried a lot to improve my thumbnails quality, even bought a paid plugin, without success. Thanks for sharing this solution, it worked perfectly well.

SOLVED:
admin>configurations>permalinks

Changed “common configurations” option, reloaded blog, and then changed back to preferred option.

(Don’t know if terms mentioned above are spelled correct, because I use WP in portuguese)

I have the same problem bere, after changing my domain name.