Joint Pics
Allowed me to create this sample image from my road tiles
It will only join 10 images wide, so I had to save the join of the first 8, save it, then add the next 8.
I had to create an empty folder and copy the single images into it, so that I could have them appear first in the image chooser. Saves a lot of scrolling.
It puts either a white, gray or black background in transparent areas, so you have to remove those out of the image afterward.