It should not decrease the photosize by using camera raw. Be aware that every time you save a jpeg it is resampled and you loose a little quality, but you would probably not notice it, until after many edits.
Thanks Curt. When you say "photosize" do you mean the actual dimension or do you mean the actual resolution/quality? The size isn't being distored but I have a hard time understanding how it could NOT be affecting quality if it is dropping the file size so drastically. How could I not be losing quality if it reduces the file size by 75%?
I just took a jpeg and edited in ACR, clicked save image and size went from 1.54 meg to 1.46 meg at quality 8-9..
When you do this make sure you are saving as jpeg and not some other format unless that is your intension.
**** At bottom is jpeg quality box. If you have it set to 2 you will get a really small file.
What edits did you do in ACR? Jpeg file size depends a great deal on image content as well as compression/quality. A decrease from 1,54 MB to 1.46 following image edits (same jpeg compression/quality) could easily come from ACR or Photoshop edits that changed compressible image detail. Noise reduction is one way, adjusting black and white points another.
To tell you the truth, you might be better off just shooting RAW in the first place... but I'm surprised by your decrease in size... I can only echo the suggestion to check the JPEG quality box and the file format used. You didn't crop it to some different resolution, did you?
PS: I'm getting into photo editing pen tablets. You might try one some time for editing.