Newbie Question on Rescaling: Maintaining Rescale

When I rescale (without resampling) and create a .TIF file, the rescale is
maintained (for instance 4"x6") when I use PS to print the photo. However,
when I rescale and create a .JPG, the rescale is not maintained (for example
it's 36"x24"!!!!!!) and I have to place a check in PS to "Scale to Fit
Media" when printing. Why does this occur and is there a default setting in
PS that somehow got changed? (I realize that just resizing the photo without
resampling doesn't change the photo data...just changes the size & increases
the resolution (in my cases I normally print on 4"x6"). Thanks in advance
for the answer to my question.

wrote

When I rescale (without resampling) and create a .TIF file, the rescale is
maintained (for instance 4"x6") when I use PS to print the photo. However,
when I rescale and create a .JPG, the rescale is not maintained (for example
it's 36"x24"!!!!!!) and I have to place a check in PS to "Scale to Fit
Media" when printing. Why does this occur and is there a default setting in
PS that somehow got changed?

Probably what happens is when you save as a jpeg the default value for
resolution is changed to 72 ppi. As you note this "doesn't change the
photo data" and is irrelevant until you go to print. You can change
this to anything you like for printing with Image Image Size,
unchecking 'resample'.