jpeginfo.1

.TH JPEGINFO 1 "06 Feb 2025"
.UC 4
.SH NAME
jpeginfo \- prints
information and tests integrity of JPEG/JFIF files.

.SH SYNOPSIS
.B jpeginfo
[
.B options
] [
.B filenames
]

.SH DESCRIPTION
.I jpeginfo
is used to generate informative listings of jpeg files, and
also to check jpeg files for errors. Program also supports automatic
deletion of broken jpegs.

.SH OUTPUT FORMATS
.I jpeginfo
supports several different output formats. Default formats are meant to be displayed
on screen, while there is also CSV and JSON formats that are easier to parse by another program.

.PP
While CSV and JSON formats always display all "columns", other formats don't display columns that
do not have any data. For example if
.I -c
option is not used to check JPEG integrity, then the `status` (and `details`) columns won't be displayed.

.PP
Similarly if MD5/SHA-1/SHA-2 checksum (hash) is not calculated, then that column will not be shown.

.SS Default Format
.PP
Default output format:

<filename> <image_width> x <image_height> <colordepth> <progressive_vs_normal> <markers> <size>

Example:
.PP
.RS 0
$ jpeginfo *.jpeg
.RS 0
IMG_1439.jpeg                    3282 x 3024 24bit N JFIF,Exif                2961607
.RS 0
IMG_1560.jpeg                    3815 x 2862 24bit N JFIF                     1045063
.RS 0
IMG_2520.jpeg                    3964 x 2900 24bit N JFIF,Exif,ICC            4712099
.RS 0
.RE

.SS Extra information format
.PP
Additional information can be displayed using
.I -i
option:

<filename> <image_width> x <image_height> <colordepth> <progressive_vs_normal> <markers> <extra_info> <size>

Example:
.PP
.RS 0
$ jpeginfo -i *.jpeg
.RS 0
IMG_1439.jpeg                    3282 x 3024 24bit N JFIF,Exif                Huffman,300dpi       2961607
.RS 0
IMG_1560.jpeg                    3815 x 2862 24bit N JFIF                     Huffman,300dpi       1045063
.RS 0
IMG_2520.jpeg                    3964 x 2900 24bit N JFIF,Exif,ICC            Huffman,300dpi       4712099
.RS 0
.RE

.SS Ls command style output format
.PP
Option
.I -l
moves filename to be last column, resulting output that is bit like output from `ls -l` command:

<image_width> x <image_height> <colordepth> <progressive_vs_normal> <markers> <size> <filename>

Example:

.PP
.RS 0
$ jpeginfo -l *.jpeg
.RS 0
3282 x 3024 24bit N JFIF,Exif                2961607 IMG_1439.jpeg
.RS 0
3815 x 2862 24bit N JFIF                     1045063 IMG_1560.jpeg
.RS 0
3964 x 2900 24bit N JFIF,Exif,ICC            4712099 IMG_2520.jpeg
.RS 0
.RE

.SH OPTIONS
.PP
Options may be either the traditional POSIX one letter options, or the
GNU style long options.  POSIX style options start with a single
``\-'', while GNU long options start with ``\-\^\-''.

Options offered by
.I jpeginfo
are the following:
.TP 0.6i
.B -c, --check
Check files also for errors. (default is just to read the headers).
.TP 0.6i
.B -C, --comments
Display file comments (from COM markers).
.TP 0.6i
.B -d, --delete
Delete files that have errors. (default is not to delete any files).
.TP 0.6i
.B -f<filename>, --file<filename>
Read filenames to process from given file. To use standard input (stdin)
use '-' as a filename. This is alternative to default where filenames
are given as parameters to the program.
.TP 0.6i
.B -h, --help
Display short usage information and exits.
.TP 0.6i
.B -H, --header
Display column names header in output.
.TP 0.6i
.B -1, --sha1
Calculates SHA-1 checksum for each file.
.TP 0.6i
.B -2, --sha256
Calculates SHA-256 checksum for each file.
.TP 0.6i
.B --sha512
Calculates SHA-512 checksum for each file.
.TP 0.6i
.B -5, --md5
Calculates MD5 checksum for each file.
.TP 0.6i
.B -i, --info
Displays even more information about each picture. Prints image coding
(Huffman/Arithmetic), density (in dpi/dpc), and whether CCIR601 sampling
was used or not.
.TP 0.6i
.B -j, --json
JavaScript Object Notation (JSON) output format.
.TP 0.6i
.B -l, --lsstyle
Uses alternate listing format (ls -l style).
.TP 0.6i
.B -v, --verbose
Enables verbose mode (positively chatty).
.TP 0.6i
.B --version
Displays program version.
.TP 0.6i
.B -q, --quiet
Quiet mode, output just the jpeg infos.
.TP 0.6i
.B -s, --csv
Comma separated values (CSV) output format.
.TP 0.6i
.B -m<mode>, --mode=<mode>
Sets the delete mode, meaningful only when used with
.I
-d
flag.
.I Mode
can be one of the following:
.RS
.TP
.B all
Files containing any type of errors/warnings, not necessary preventing
the decoding. (default)
.TP
.B erronly
Only files with serious errors (i.e. cannot be decoded at all).
.RE
.TP 0.6i
.B -, --stdin
Read input from standard input (instead of a file).


.SH Known JPEG Markers
.I jpegoptim
scans through application (APP) markers in the JPEG image and will display information about "well known" markers
found in the image. Markers found in image are listed in the "markers" column.

.SS Known Application Markers

Currently
.I jpegoptim
recognizes following common application markers found in JPEG images:
.RS 1.2i
.TS
tab(@), left, box;
c | c
lB | l.
Marker Name@Description
_
JFIF@JPEG File Interchange Format
JFXX@JFIF Extension
Exif@Exchangeable Image File Format
XMP@Extensible Metadata Platform (Adobe)
ICC@ICC Color Profile
IPTC@IPTC (Adobe Photoshop)
Adobe@Adobe
AdobeCM@Adobe Color Management
CIFF@Canon Raw
AVI1@AVI Video
QVCI@Casio QVCI
FLIR@FLIR
FPXR@Kodak FlashPix
MPF@CIPA Multi-Picture Format
Meta@Kodak Meta
Stim@CIPA Stereo Still Image
JPS@JPEG Stereo Image
Scalado@Scalado
RMETA@Ricoh Meta
EPPIM@Toshiba PrintIM
NITF@National Imagery Transmission Format
GoPro@GoPro
SPIFF@JPEG Still Picture Interchange File Format
AROT@Apple
HDR@JPEG-HDR
.TE
.RE

.SS Other Markers
.PP
If image contained any unrecognized application (APP) markers then "UNKNOWN" is added to the list of found markers.
.PP
Additionally if image contained any comment (COM) markers then "COM" is added to the list of found markers.


.SH EXIT STATUS

Program returns 0 on successful run. Non-zero exit status is returned if there were any errors.

When using --check (or -c) option return value is non-zero if one or more of the files checked had any errors.


.SH "SEE ALSO"
jpegoptim(1)

.SH AUTHOR
Timo Kokkonen (tjko@iki.fi)

.SH COPYING
Copyright (C) 1995-2025  Timo Kokkonen

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.