I bought the Street of Legend set. I need 6" tiles, but also few 3" tiles.
But the 3" have only 2 tiles on one page and I want to have more on one page.

I had no problems with copying the file into irfanview, rotate it and trying to copy it 6 times in paint. But if I try to print it, I don't have 3 inches anymore.

I'm not very experienced with painting applications. Can someone help me?

I'm not familiar with the illustration program you are uing.
But my main question is whether you are printing it out with "no scale" selected. If not, you aren't guaranteed it will print at the proper size.

Test prints from the pdf reader with 3" and 6" are in the correct scale after I printed them. Same with all the 6" printouts on the correct paper.

But I do not want only 2 street tiles with 3" to print on one page. It would be paper wastage.

So I would like to copy a street tiles 6 times on a picture and print it out. But copying it into a grafic program (like irfan view and paint), change the size. I'm not sure if Gimp or other free software could do it, for me to print it in the correct size, but I do not know this software.

One thing to check is to see if the resolution is the same for the WWG pdf and the graphic after you copy and paste into your graphics program. Some graphics program have a default resolution that does not match the resolution of the WWG pdf so when you paste the WWG graphic you copied from the pdf into your graphics program the size will change. I think, but am not sure, that the resolution of the WWG pdfs is 300dpi. Check the resolution of the graphic you see after it is pasted into your graphics programs and change it to match the original WWG pdf resolution.