Hi Alexred,
your solution works perfect with Google PicasaWeb. I can set the ordering of images by filename which is important for me. When I change the image sorting order in PicasaWeb it appears immediately in Ozio Gallery.
But... The bad news: Google announced he will retire PicasaWeb in the near future in some months... And they say, we should use Google Photos instead, because that product is much better... Well: Google Photos is a wrong, absolutely unuseful product. For example there is no option to set the image order by filename...
And this is absolutely bad news for me.
When I set the sorting order in PicasaWeb it appears in Ozio Gallery, but this order is not shown in Google Photos.
And anything I change in PicasaWeb that is appear in Ozio Gallery, but not in Google Photos. And anything I change in Google Photos, nothing happen in Ozio Gallery...
So your solution is perfect for now, but what will be in the future?
What should I do?
I like Ozio Gallery vey much, this is an awesome component, but if I will be unable to change the image order by filename, I won't be able to use it in my site

Could you Carneade to find a solution in the future?