So they say if you save a JPG image lots of time, the image starts to lose information...
If I open up a JPG image in Photoshop, make some edits, then use the 'save as' command (using a lower quality setting), overwriting the current file open, will saving it again further compress the image that is currently open? Or does photoshop store the original file (when it was first opened) information until closed?
JPEG is a lossy-compression format.
You lose image quality by compression each and every single time the image is saved and closed, no exceptions. That means that even on the first save you lose quality, even at maximum quality. Whether the loss can be perceived is a different question.
Message was edited by: station_two
Unfortunately, I think station_two may have misread your question slightly.
You could save an open document over and again 100 times, and as long as the document remains open the last save will have exactly one level of JPEG compression applied to it. The document does not accumulate compression loss by the Save operation as long as it is kept open.
What may confuse the issue is that Photoshop will show you a preview of how the JPEG compression looks just DURING the save if you check the [ ] Preview box in the JPEG Options dialog.
Only if the document is closed, then the saved JPEG reopened and saved again will you accumulate loss from compression.
I read the OP correctly, but I omitted two words in my respomse. I have edited my post to read:
You lose image quality by compression each and every single time the image is saved and closed, no exceptions.
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