The cropped image height and width changes to the height and width text fields values specified in the option bar of crop tool. When you choose "Use Photo Ratio" , the entries of height and width text fields values are same as original image. That is why it remains the same.
Do reply if you have any questions.
Thank you for your input but I'm still confused. It should behave like No
Restrictions and all the other crop settings in that it should eliminate
the unwanted pixels and automatically reduce the pixel width and height by
the cropped amount except that the crop would be limited to proportional
reductions so that the aspect ratio of the original photo is maintained.
Instead, it crops the unwanted pixels but leaves the pixel width and
height, resolution, and number of pixels the same. I assume this means that
it has to upsample the remaining pixels which must loose picture detail. I
shouldn't have to know what the desired width and height should be before I
crop any more than I need to know them when I use No Rrestrictions.
Furthermore, if I do try to change the dimensions, the aspect ratio setting
changes to Custom or to one of the preset settings if that's what I choose.
And when that happens, the pixel dimensions are changed appropriately.
When you choose "Use Photo Ratio " options the by default fields of W, H and resolution is same as your images.
So if you do crop then no of pixels in the image remains same , because no of pixels= resolution x (W x H )
And application upsamples the extra pixels.
If you do not want to upsmaple the image pixels choose custom value.
Thank you all. I think I figured out how to crop using "Use Photo Ratio"
with Crop tool so that I can ensure that my photos are cropped only
proportionately and PSE 10 doesn't upsample pixels:
1) Select Crop tool.
2) Set "Use Photo Ratio" in Aspect Ratio setting in Options bar if not
3) Make crop selection as usual but don't complete (commit) crop. Will
only be able to crop proportionately.
4) When ready to complete crop, change Aspect Ratio setting to "No
Restriction" which blanks out width, height and resolution setting.
5) Complete (commit) crop as usual.
Photo will be cropped proportionately, width and height will change
automatically to cropped size and pixels will not be upsampled avoiding
lose of detail, that is, PSE will behave as though No Restriction had been
specified from the outset. Blanking width and height before making crop
selection forces either Custom or No Restriction setting which means that
PSE will let me make non-proportional crop.
PS. IMHO I think making "Use Photo Ratio" force upsampling is NOT a good
"design feature" when you are not warned about it and are not given a
choice to not make it upsample.