How do I open images as locked/background layers by default?

[OurGazebo]

Generally for personal use, I need to just make simple adjustments, and it's tedious to have to always flatten the image so it will save to the same format. I can't find a way to change this preference in the settings.

[AlanGilbertson]

An image that is already flat (a jpeg, for example) will open that way, with the usual "Background" as the only layer. Some PNGs are single-layer, but not all, and any image with transparency is by definition not flat, so won't open that way.

If it doesn't open with just a background layer, then it was saved in a layered format. You can automate flattening it by using an Action that would just have one step: Layer > Flatten Image. Assign a keyboard shortcut to the Action (or just to the Flatten Image command). You would not want to make this a default on opening any image, because then it would flatten the rare things you don't want to change.

[Amy26768499wxbx]

Unlike in previous versions of Photoshop, in the more recent versions, all image files I open, regardless of format, open as "Layer 0." I assumed it was a change in Photoshop's defaults. 

As part of personal projects I open many, many images of varying formats -- but mostly JPG and PNG -- and none of them have opened as a background layer in a long time, like several months to a year or more (I haven't kept close track). 

[AlanGilbertson]

There's been no change in defaults. Might be worthwhile resetting your Photoshop preferences. That's always a good early step for troublshooting weird behavior.

[OurGazebo]

Oops, that reply from "Amy" is me, the OP -- replying from the wrong account. 

[Stephen Marsh · Accepted solution]

@OurGazebo 

The Script Events Manager can be used to automate this via an action or script tied to the open event.

https://prepression.blogspot.com/2021/10/photoshop-script-events-manager.html?m=1

[OurGazebo]

Thank you, I guess that will work if I can't change any Photoshop settings.

[Stephen Marsh]

Perhaps you have mistakenly set Script Events Manager already, but to create a layer from Background (there is a script for this that ships with Photoshop).

[D Fosse]

@OurGazebo 

Something's not right here. Photoshop won't open as a floating layer unless the file was saved that way. There are no "changed defaults".

And a jpeg simply can't be Layer 0, the jpeg file format specification does not support it.

Where do these files come from and how are they opened?

[OurGazebo]

Usually from various social media platforms. Maybe my memory is wrong. And in fact I do save a lot of them as PNGs as I'm downloading (with an extension). But I uninstalled/reinstalled and I will use that script to just open all files flat by default.

[OurGazebo]

Okay I realized what is happening with jpegs that I had forgotten. If I crop them, they turn into Layer 0. That coupled with PNGs always being layered is what was causing me to think all image files now opened that way. 

So now my question is, how do I prevent the unflattening?

[D Fosse · Accepted solution]

It sounds like you have the crop tool set to "hide" cropped areas instead of "delete" cropped areas.

A flat image can't have content outside the canvas, so for this to work it has to be converted to a floating layer.

If you don't crop it won't happen.