I thing the only changes i did were:
-At the "In file taxanomy-skills.php there was an offset in line 18 set to -1 and it should be 0" as Argone said in other post
-And Also change portfolio page name to "galeria".
-Post "works" posts adding "Use cu…
Hope this can help,
when you add your image to "works" what after you can see at "portfolio", be sure, to select "custom thumbnail" option then select the image and click "use this image" button.
Good luck!