Xml picture gallery problem

Can someone please help me with this. I’ve been trying to figure out how to use this gallery:The gallery with thumbnails and multiple galleries (both mx and mx2004 files)V3_with_thumbs zip

I can not make it work with my picture.
I changed the picture in the pic folder with 3 picture of mine, I kept the same names pic1, pic2 and pic3.
I changed also the thumbs with 3 new files and I kept the names th1, th2, th3
BUT when I publish my file those 3 pictures and thumbs do not show.

What am I doing wrong?
thanks

Let me add one note.
The size of my pictures and thumbs is different than the size of the original ones.