For those among us that are unable to program, I found a way to "work around" the skin bug, you'd need however to have access to the database in edit mode -in my case I used enterprise manager-, here is what I did:

• Created a new Gallery instance and gave it a one character name "x".
• Went ot the admin area and provided all gallery parameters.
• Opened Enterprise Manager and loged on to my DNN database
• Went to the y_ModuleSettings table (where y is the prefix of the DNN database).
• Scrolled down to the "SettingName" column corresponding to the gallery module whose name is "x" and changed the value of "skin" and "theme" simultaneously to "DNNSilver" or "DNNGray" or "DotNetNuke".
• Went back to the gallery administration interface and selected the same vale I entered in the database for the skin.
• Clicked on save et voila! (if one doesn't click on save the gallery skin does not update -but that's another story)

I know is not clean, neither elegant but it works without recompilation or programming.

Cheers,

Ivan