Filesize witch-craft! Please explain

[ballstothis]

Can someone please explain what kind of black-magic witchcraft is going on here?

I received this huge PSB layered file, which I trimmed down, flattended and saved as /saved a copy.

I've tried JPG & PNG, whatever I exported flattened file comes in at 102 MB.

I've checked the file is 8bit, RGB. I've reduced the size to 432px X 648.

Also, the finder details say 24bit even though it's 8bit in working form.

I just can't explain it. Is the file corrupt? 

[Conrad C]

The 24-bit part is probably easily explained:

Photoshop says it’s 8 bits/channel.

File Properties says it’s 24 bits.

Those are the same thing: 8 bits per channel * 3 RGB channels = 24 bits total.

The file size is more of a mystery. In my tests, a 432 x 648 image should be 200-400KB in JPEG or PNG.

In Photoshop:

When you choose Image > Image Size, at the top of the Image Size dialog box what does it say for Image Size (in K) and dimensions?

When you choose File > Save for Web (Legacy), what does the file size preview say for JPG and PNG?

If you select the same file in Adobe Bridge, or another image editor, what does it say the file size is?

What media is the file stored on, a typical computer SSD or hard drive, removable media, network storage…?

[ballstothis]

Hey Conrad,

Thanks for your input. I've been using Photoshop professionally for years but this is really weird. FYI, I've just updated photoshop to the latest version but i'm still having the same issues. 

Something really screwy is up with the image itself. I've never seen this before.

I create a blank image 432px x 648px 150ppi 8bit. - Saved as JPG comes out at 18.7KB

I then paste my 'problem' image (with no filters or anything) at the exact same proportions, ontop of this file. Checked that the dimensions are identical (no oversized layer), flattened and save JPG. Comes out at 102MB?

[ballstothis]

Here's a view of the files in Bridge. Showing the various sizes and scales. Very strange.

This only happens when I paste or use the flattend image I was supplied.

[D Fosse · Accepted solution]

This is probably DocumentAncestors metadata. This is a complete record of copy/paste/place operations, and it can grow to enormous sizes for templates and so on that have been reused ad infinitum. As the purpose dictates, this will travel along in a paste.

Export and Save For Web will strip out all this metadata.

[ballstothis]

Yup! That solved it. I'm assuming this option is somewhere in preferences? I've never seen this before. 

Thanks for your advice!

[D Fosse]

Actually it isn't in Preferences, but @Stephen_A_Marsh has a script to remove it. He should get a notification with this.

It is supposedly for forensic purposes, but given how easy it is to remove it, it's hard to see the point. Anyway, if you have problem files, you can run them through Export/SFW to clean them out before further use.

[Stephen_A_Marsh]

@D Fosse 

Thanks, yes I did get the notification, more here:

https://prepression.blogspot.com/2017/06/metadata-bloat-photoshopdocumentancestors.html

[ballstothis]

Thanks guys. In all my years, i've never seen this before!

[Conrad C]

The problem seems to be specific to that one image, because the problem doesn’t happen when you start a document from scratch. Now I’m thinking it shows symptoms of a bug previously discussed here, where certain metadata becomes absurdly large. I’m not intimately familiar with it, but if you follow these links and see if anyone’s suggestions help, that might get you somewhere.

Inflated JPG File Size - Photoshop Document:Ancestors Metadata

https://www.google.com/search?q=photoshop+file+size+ancestors+bug

[ballstothis]

We solved it Conrad. Thanks again for your efforts!