Using GIMP 2.8.22, Can I Undo "Merge Layers"?

[Songbird]

... And does "Flatten Image" merge all the layers?

[Ofnuts]

1) If the XCF is still open in Gimp, then yes, use Edit > Undo (or Ctrl-Z). If you have already saved the XCF, or reloaded an exported image (JPG/PNG) then no (in some simple cases you can re-extract something from a uniform background, though).

2) Yes. But It should rarely be used, if ever. Flattening is done automatically and on the fly when you export to a "flat" format (JPG, PNG...). The "normal" workflow is to keep an XCF with all the layers/selections/paths, and export a JPG/PNG from that for "presentation" (web, print...).

[rich2005]

(07-20-2022, 06:04 AM)Songbird Wrote: ... And does "Flatten Image" merge all the layers?

Once merged or flattened you can recover, as an undo (ctrl-Z), only for the session. Come back the next day and the image is fixed.  Save as a Gimp .xcf to keep all layers and get in the habit of making incremental backups. 

There are ways to mitigate this. Instead of merging use Layer -> New From Visible and use the new layer as a 'staging point' The un-merged layers below this layer.  It all comes with use and practice.

Merging, does what it says. Either From the Image menu or in the Layers menu Merge Down which combines two layers. Flatten merges all layers and removes the alpha channel.

For the final image that you use, then export as a png which keeps any transparency (= merge) or export as a jpg which loses transparency (= flatten)

[Songbird]

(07-20-2022, 07:13 AM)Ofnuts Wrote: 1) If the XCF is still open in Gimp, then yes,  use Edit > Undo (or Ctrl-Z). If you have already saved the XCF, or reloaded an exported image (JPG/PNG) then no (in some simple cases you can re-extract something from a uniform background, though).

2) Yes. But It should rarely be used, if ever. Flattening is done automatically and on the fly when you export to a "flat" format (JPG, PNG...). The "normal" workflow is to keep an XCF with all the layers/selections/paths, and export a JPG/PNG from that for "presentation" (web, print...).

Thank you!