When I merge 5 photos which are 5 MB JPGs into a panorama by choosing "Merge to panorama in photoshop" from Lightroom, and save the resulting image as a .TIF, the file size becomes 650MB! Then, when I flatten layers and save again, it reduces to 111 MB.
Why does this happen? Is photoshop creating new information? How can I save it in a format that doesn't lose any pixels, but also doesn't increase in size? The max size should be no more than 5 * 5 = 25Mb, right? Because photoshop cuts out the images in the right pattern and stitches them together?