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If one downloads this image to their computer and opens it in Photoshop, they will notice something very interesting in the Paths panel:

enter image description here

Several paths are included in this file, one for the laptop's logo, one for the laptop, one for the screen and one for the reflection.

I thought this type of information was only available inside a Photoshop file. But it is a JPG.

I am surprised, and I'm also wondering how one can embed path info inside a JPG.

5

Photoshop has had the ability to save paths in JPGs for a while. (CS5.5 I think, might have been CS6)

As long as you don't use Save for Web and use Save As for JPG, they'll be there if the jpg is subsequently opened in Photoshop.

Other software may not see the paths.

It's similar to how Fireworks used to save PNGs with layers... it's all proprietary data that is superfluous to the overall format. But can be read by the same proprietary software.

And note, the extra data will affect file size (kb)

  • Are there any other mysteriously secret "hacks" of the same style that allow Photoshop to save its own data in a JPG? I'm very curious. – MicroMachine May 24 '18 at 22:44
  • 1
    Well, I don't really know. I've never really explored what could and could not be saved in various formats. I remember the "paths in JPGs!" from Adobe marketing. and I've used that a few times myself. – Scott May 24 '18 at 22:47
  • Features like this are definitely "under"-marketed by Adobe! – MicroMachine May 24 '18 at 23:13
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Paths in JPG exist in other software, too. Serif Affinity Photo and -Designer know them. In Affinity Photo one can have masks to hide parts of the image. For example one active vector path mask for background removal and a few disabled masks for optional hiding or selecting later some important parts.

When saving as JPG the dialog allows to convert masks to paths. That makes a JPG, which in Photoshop has paths in the Paths panel. In Photoshop those paths are inactive, one must manually take them into use.

When opened in Affinity Photo, active masks work and hide parts from the image, you see the transparency checkerboard. Disabled masks can be enabled and hide more. Masks can be released, which makes them editable path layers.

Obviously there's no common agreement how JPG extensions should work.

In your other question of "Arithmetic coded JPG" we met another extension. Serif Affinity series opens it but as opened it's like an ordinary JPG.

IrfanWiew says about it: "This is not JPG, but a WEBP image - do I change filename extension from JPG to WEBP?" IW opens it like a JPG.

I haven't seen nor tested a way - to save WEBPs and - to see, if there's transparency.

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