How can I compare an edited image with the original without losing my changes?

Separate the two jobs: comparing and experimenting. For a quick comparison, use an app’s built-in before-and-after preview, if it has one. For experiments, make a duplicate or another clearly separate working version first. That gives you a distinct version to compare with your new attempt.

If you use Apple Photos on Mac, its guide says you can open the image in Edit view and hold the Compare button or the M key to temporarily compare the edited image with its original. It also documents duplicating a photo before trying different edit versions. [S1] These are Photos-specific instructions; controls in other apps may differ. The guide doesn’t establish that every app handles originals, versions, or saving in the same way, so check your app’s instructions before relying on its behavior.

Open the photo in Edit view, then hold the Compare button or the M key to view the original temporarily, according to the Photos guide. [S1] Because the guide describes holding the control, use it while you want to inspect the original, then release it to return to the edited view.

Look at a few specific things rather than relying only on a vague impression: the subject’s appearance, the crop or framing, and any areas you deliberately changed. You can note what looks better or worse as you switch between views. If your app’s controls don’t match these instructions, check its help for the comparison control rather than guessing at an unfamiliar command.

Create a separate version before experimenting. In Apple Photos on Mac, the guide documents duplicating a photo before trying different edit versions. [S1] If your app allows it, give the copy a clear name or label and keep the current version identifiable. Then make the stronger edit on the duplicate and compare the two versions.

For example, you could use labels such as “Current working edit” and “Stronger contrast test” if your app supports names or notes. These are suggested labels, not special Photos features. Don’t assume that an export, undo history, or an app’s save behavior is a substitute for a separate copy unless you’ve confirmed how that app handles it. The Photos guide cited here doesn’t specify file storage, backups, or version-history behavior.

Use this short routine:

1. Identify the image you’re editing and the version you want to preserve.
2. Use the app’s temporary compare control to inspect edited versus original. In Photos on Mac, use the Compare button or M key in Edit view. [S1]
3. Before a new experiment, duplicate the image or create a separate working version. Photos documents duplication for trying different edit versions. [S1]
4. Make one planned change at a time, then compare the candidate with the version you preferred before.
5. Choose the version that best meets your purpose. Before removing another version, confirm how your app saves and manages copies.

Example decision note: “Keep: current working edit. Test: stronger contrast. Check: subject detail and crop. Decision: [keep current / keep test / compare again].” This is a reusable note, not a guarantee that an app preserves versions automatically. When unsure about saving or duplication, check the app’s instructions before making a change you may not be able to reverse.