I found the following BUG.
I have 165 JPGs. (large geo-map). Collaged should this be a map with 10 Rows and 15 Columns.
The JPGs are squareformat. 700x700
Only the last colum and the last row have another sitze.
The most right pictures have the same hight like all. But only 200 in width
The lowest JPGs have full width like the other but only a hight of 400
And the absolute last is 200 x 400
XNVIEW adds the last JPG in a row correct. I have 14 and a half Pictures side by side
But the lowest row ist scrambeld. XNVIEW tries to stretch the absolute last JPG in 2 directions. Ans with the result ist deforms the othe in the last row.
I have reduced my 165 JPGs for testing to 15. It means 3 rows with 5 cols.

Explorer shows the last picture stretched. It has only 200x400
When I use the collagefunktion the result looks like this:

This is scrambeld too in the last row.
The 1. and the 2. Rows are ok. The last (3.) row starts correct. But the rest is stretched to 1 1/2 rows
I have placed these 15 JPGs in http://www.gerud.de/XNVIEW/Testmap.zip
It would nice if you can fix this bug (unnecessary stretching the last row/col picture)