I still not resolve the problem. I sure, that I'm doing something wrong or forget to do something. I create some test site on the localhost by Denwer. There is my actions from the beginning step by step:
- create new site, installed Joomla 1.6.3
- install com_phocagallery_v3.0.0
- install and enable plg_content_phocagallery_3.0.1
- create new article named "Testing Phoca"
- create new menu item itn the main menu as a single article and link it to "Testing Phoca"
- create new folder named Cat1 in the X:\home\localhost\www\pt\images\phocagallery folder
- create file named watermark-large.png and place it to the Cat1 folder
- copy come image named "screen01.jpg" to the Cat1 folder
- configure Poca Gallery options:
- Detail View Settings-Detail Window-HighslideJS
- Description Settings-Display Description In Detail View-Show(Lightbox)
- Watermark Settings-Create Watermark-Yes(folder)
- Images And Detail Window Size Settings-Detail Window Width=800 and Detail Window Height=600 (all my images are 800*600
- create new category in the Poca Gallery "Cat1"
- add image throw Images in the Poca Gallery
- add text "Description for this image" in the description field of this image
- add code
{phocagallery view=category|categoryid=1|limitstart=0|limitcount=28|detail=4|displayname=0| displaydetail=0|displaydownload=0|imageshadow=shadow1|displaybuttons=0|displaydescriptions=1}
to the article "Testing Phoca" and save it
When I open my test site in the browser and open my article, I see my text and the thumb of my image.

If I click on the thumb I see window with the thumb :

Where is my mistake?