The big file contains very bulky metadata that seem related to "Document Ancestors" (whatever that means), as demonstrated using exiftool
(*):
Small file:
ExifTool Version Number : 12.40
File Name : 2.jpg
Directory : .
File Size : 610 KiB
File Modification Date/Time : 2023:04:26 23:46:39+02:00
File Access Date/Time : 2023:04:27 08:25:33+02:00
File Inode Change Date/Time : 2023:04:27 08:25:10+02:00
File Permissions : -rw-r--r--
File Type : JPEG
File Type Extension : jpg
MIME Type : image/jpeg
Exif Byte Order : Big-endian (Motorola, MM)
Orientation : Horizontal (normal)
X Resolution : 72
Y Resolution : 72
Resolution Unit : inches
Software : Adobe Photoshop 22.5 (Macintosh)
[etc....]
Big file:
ExifTool Version Number : 12.40
File Name : 1.jpg
Directory : .
File Size : 72 MiB
File Modification Date/Time : 2023:04:26 23:46:39+02:00
File Access Date/Time : 2023:04:27 08:25:17+02:00
File Inode Change Date/Time : 2023:04:27 08:25:10+02:00
File Permissions : -rw-r--r--
File Type : JPEG
File Type Extension : jpg
MIME Type : image/jpeg
Exif Byte Order : Big-endian (Motorola, MM)
Orientation : Horizontal (normal)
X Resolution : 72
Y Resolution : 72
Resolution Unit : inches
Software : Adobe Photoshop 22.5 (Macintosh)
Document Ancestors : 0, 0000471C09D4159FD6238FB4FD814C8D, 000076180AF04FD351A948E221782809, 00007690EE61955F5FD43EA8AF3C1304, 0000A6C7815905497C2762FB3073AC1B, 0000FE4F1FBA4CC1FCE5458F3A9761FB, 000157BB4EC66C832CEA7D49818F2BB7, 00017C97C28B0C407DB5E9F93F00B063, 0001B7F957AD0C86828CD343E87AEC1C, 0001D40A7B18F3382B14F2E780D08129, 0001E457A018BB7DC721DC767178D01B, 00020F3718874DEC579311A3537474EE, 000221B48B15CB3F04C863946D256D35, 0002842703441D4A10B778F919DB2C49, 0002B0E39668FE325CA514C4B5BE725D, 0002D4A76613A872D72F9F2696C778E9, 000331F19A13944845140188375C7674, 0003C8770168CFEB622F1A6523EA33CE, 0004EAB42FF2EEBC5DB3FCB6B879B558, 0004F219969ECF9B707A9B90C0D00CD1, 0A829E927819B4D576B0B45AADE12D, 000AB192EC844703B32FE95585910613, 000ABA1A699C389D573DBC0C7944D2C3, 000B31C4C6A0712A9EA701121B2AF287, 00D758B3CD8D758A5539C67FABC7E0C8, 00D76CFCF8B72167E9DFED384D0F7942, 00D775CF9F469FBAF615184FEB8DA3AF, 00D7A0DE840C484B767F4D68CF94477D, 00D7A4FDB541A9BFB611BDA0834208C4, 00D7A8F02240527311744902D1AE411E, 00D7B29953042F6D84A60C6BD4852931, 00D7CEAB897F54801CC1E218F7EE6E28
Warning : [Minor] Extracted only 1000 photoshop:DocumentAncestors items. Ignore minor errors to extract all
History Action : created, saved, saved, saved, saved, saved, saved, saved, saved, saved, saved, saved, converted, derived, saved
History Instance ID : xmp.iid:44a09451-dbf1-4275-b9fd-af392f197c12, xmp.iid:c384f05b-6324-451b-8469-98eb9cd9c98e, xmp.iid:7382e449-a14c-466c-b5f0-c2ec0d934da8, xmp.iid:7620c5de-1242-4e61-ab37-134c0049fa15, xmp.iid:985c9ea0-d8ef-42e8-a417-e4d3a2b24b02, xmp.iid:c705addc-4a2d-4758-8408-684745076736, xmp.iid:dac71b79-740d-4100-bbd0-8fbdace87867, xmp.iid:becd1e89-1eef-43ba-9b56-889db8a7782a, xmp.iid:ae6fe371-a95e-4e62-9262-3d133c4cab5d, xmp.iid:92376da9-b3cc-4b29-a778-9275c0e3c5e3, xmp.iid:98ba57f7-dd9b-4664-bbc1-bbb03ba1d520, xmp.iid:2c3073ce-5c16-45b2-95f2-5d62889092d5, xmp.iid:6ac41532-5cab-43c0-afa3-9a2f7d22ed2f
History When : 2021:08:18 10:22:30-04:00, 2021:08:18 10:37:03-04:00, 2023:03:26 18:23:29-04:00, 2023:03:26 18:36:43-04:00, 2023:03:26 18:41:57-04:00, 2023:03:27 18:28:31-04:00, 2023:03:27 18:29:04-04:00, 2023:04:07 18:09:45-04:00, 2023:04:07 21:30:55-04:00, 2023:04:08 14:52:38-04:00, 2023:04:09 11:17:05-04:00, 2023:04:26 17:00:30-04:00, 2023:04:26 17:00:37-04:00
History Software Agent : Adobe Photoshop 22.4 (Macintosh), Adobe Photoshop 22.4 (Macintosh), Adobe Photoshop 23.4 (Macintosh), Adobe Bridge 2022 (Macintosh), Adobe Photoshop 23.4 (Macintosh), Adobe Photoshop 22.5 (Macintosh), Adobe Bridge 2022 (Macintosh), Adobe Photoshop 23.4 (Macintosh), Adobe Photoshop 23.4 (Macintosh), Adobe Bridge 2022 (Macintosh), Adobe Photoshop 23.4 (Macintosh), Adobe Photoshop 22.5 (Macintosh), Adobe Photoshop 22.5 (Macintosh)
History Changed : /, /, /metadata, /, /, /metadata, /, /, /metadata, /, /, /
History Parameters : from application/vnd.adobe.photoshop to image/jpeg, converted from application/vnd.adobe.photoshop to image/jpeg
Derived From Instance ID : xmp.iid:2c3073ce-5c16-45b2-95f2-5d62889092d5
Derived From Document ID : adobe:docid:photoshop:2dab377d-52d8-e34f-9b73-f2f80c061c2b
Derived From Original Document ID: xmp.did:44a09451-dbf1-4275-b9fd-af392f197c12
[etc...]
Note: Data is way bigger that what is shown here because
- As mentioned in a
Warning
line, exiftool
only extracted the first 1000 DocumentAncestors
values.
- I had to truncate further to fit the size limit of posts.
- The data is formatted as an XML data structure and XML isn't known for its conciseness; people jokingly say that XML stands for
eXtreMely Large
.
This seems to be a known problem.
You probably have options to not save EXIF/XMP metadata in your software. Later comments pointed at a Save for web
option in Photoshop.
Otherwise you can also use exiftool
to remove selected metadata:
> # Remove the data with exiftool
> exiftool -DocumentAncestors= 1.jpg
Warning: [minor] Excessive number of items for photoshop:DocumentAncestors. Processing may be slow - 1.jpg
1 image files updated
> # Show resulting sizes:
> stat -c "%8s %n" *.jpg*
630629 1.jpg
75475852 1.jpg_original
624943 2.jpg
So you can see from the above that without the ancestors the file sizes are equivalent.
If you create your file from existing sources, you may be inheriting their ancestors, so you could use the command above to prune the history of these files.
(*) exiftool
is the canonical CLI utility to explore & edit image metadata. Available free for all platforms.