Question on Saving Photoshop CC 2017

[scoostraw]

When saving a png file as a jpg, PS still displays the original png on the screen.

Is there a way to change preferences where once it is saved as a jpg the newly saved jpg is displayed on screen instead?

[JJMack]

Before you save the jpg. If you flatten the document in Photoshop  to a single background layer to remove any transparency when you save as Jpeg the document  in Photoshop will switch to be the Jpeg document  the opened png file will not be touched the document in Photoshop  backing file will be switched to the jpeg file and the document  name will change from what was open to the saved jpeg file name the name you saved it as.

[scoostraw]

Hi JJMack.  Thanks for the reply.

That is indeed what is happening.  I am working with mac screen shots, which get saved as png files.  I got tripped up because I'm pretty sure in the past, on an older machine and an earlier version of PS, I did not have to flatten the png before saving to jpg - and PS switched the screen to the jpg.

I don't THINK I'm mis-remembering this..(?)

[JJMack · Accepted solution]

My memory I don't trust.  I trust my minds thinking ability more.  See if my thinking helps memory.

If the open document in Photoshop is layered you can save out a Jpeg version of it. The document in Photoshop will not be change it will be layered and the saved Jpeg will not be opened.   

If a Document open in Photoshop has a single layer and contains transparency you can save out a jpeg but the jpeg file will not contain any transparency for jpeg file format does not support transparency. The document in Photoshop will still contain transparency.   A jpeg can not.

[scoostraw]

Well at least I wasn't mis-remembering.  My old mac saved screen shots as single-layer png's.

My newer mac saves them as png's that must be flattened to save as jpegs.  So I thought that photoshop was doing something different.  But it isn't.

Thanks again.