It's not very big as I was only able to add some of the photos I wanted to it - 179 of 260. Even at that I had to do it in pieces, adding 50-60 photos at a time & saving the project after each group added - unless it hung up. By saving, I meant I was going to File\Save Project. I think it's currently at about 18 minutes. (This project is on my home computer & I'm at work now.)
I had first tried creating the slideshow from within myDVD, but after seeing a post about creating the slideshow then adding it to myDVD I also tried it as a new project that way. Regardless of which program I used, it only worked if I added about 50-60 at a time, and in every instance would hang after reaching about that same point - 180 or so photos.
I don't know if it makes a difference or not, but I had this same problem last year with the NXT version & essentially broke it all together when I deleted temp files (as was suggested in some post I read at that time) then couldn't find my original installer CD when I was later prompted for it. I purchased NXT2 at that time & when I installed it, it showed it was uninstalling the previous version. I've never gotten it to work though. I was just trying it one last time before I trash it & go to a different product.