P: Allow JPEGs to be embedded, to save disk space

[Lee James]

Problem:
Let's say my client sends me a 4Mb JPEG file which needs retouching for a project. I open it in Photoshop, add a couple of simple adjustment layers, and save the image as a psd. The resulting file is now 65Mb. This waste of disk space is totally unnecessary, since all I've added to the image is a couple of adjustment layers. And if I'm working on, say, a magazine containing hundreds of photos, the amount of wasted space really stacks up.

Solution:
Whenever you open a JPEG in Photoshop, it appears as an 'embedded JPEG layer'. This operates a lot like a Smart Layer. You can apply effects to it, but the layer itself is not regarded as editable bitmap data (unless you rasterize it). Then, when you save it, the original JPEG remains embedded in its original JPEG format, so if you haven't added any raster layers, the file size should be only slightly larger than the original JPEG.

[Lee James]

But if all your layers are just copies of a 1 meg JPEG file, why should any pixel data be saved other than the 1 meg JPEG file?

[Lumigraphics]

Because its not a 1 meg JPEG file. Compressed and uncompressed are two different things. You just said that you don't want lossy compression.

[Lee James]

I feel like you're misunderstanding what I'm asking for.

I am a designer and I work in Photoshop. I don't want to lose my Photoshop documents, nor would I ever save a Photoshop document as a JPEG because that would destroy all the layer data, make it lossy, and uneditable.

What I'm trying to do is bring JPEGs into a Photoshop document and retain them as JPEGs instead of converting them to raster data.

Now with the help of another user here (Max Johnson) I have found out that Photoshop already allows you to do what I want and embed JPEGs (just go to File > Place Embedded and import the JPEG that was). The problem is that these files are STILL being saved as raster data, making the document far bigger than it needs to be.

[Lee James]

For the record, I've done a similar test myself and here are my results:

1. Completely empty Photoshop document with a white background (3000x3000 in size)
= 650k

2. Same document containing a 836k JPEG embedded as a smart object, shrunk down in the document to a tiny size
= 1.8 meg

3. Same document with the JPEG smart object now filling the entire document
= 25 megs

4. Same document with the single JPEG smart object copied several times, flipped, warped, distorted etc.
= 31 megs

5. Same document with all the layers set to invisible
= 23 megs

6. Same document, but with the full-size JPEG moved to the very top - meaning it looks identical to document (3) above
= 34 megs

7. Same document, but with the embedded JPEG blanked to white, meaning all the copies are white
= 3.1 megs

Conclusions:

• Embedded JPEG smart objects really are retained as JPEGs, meaning no space is wasted on the smart object itself.
= Efficient storage

• However, every single instance of the smart object in the document is saved as (compressed) raster data. Even instances that are hidden or turned off - they're still being saved as (compressed) raster data which adds to the filesize.
= Inefficient storage

I see no need for this. All Photoshop should reuiqre is the original JPEG, information about where each instance is positioned, and a single preview image, which should be of limited resolution. I'd be quite happy for all my preview images to be limited to 1920x1080 and use maximum quality JPEG compression.