Lars said:
Is there any freeware to join together two image files?
Such as JPEG, GIF, TIFF, etc?
Do you want them to overlay each other or side-by-side?
Irfanview can do a very basic side-by-side. Go to Image->Create new
Panorama image. Select horizontal or vertical, add your pictures, then
click on create image.
To overlay, you'll need something like Serif's PhotoPlus that supports
layers and transparency settings.