Fixing Dates in Image EXIF Tag Data from Linux

gmendoza — Mon, 22 Jun 2009 06:11:51 +0000

I recently needed to organize a large number of old digital photos that had the wrong date embedded in their EXIF tag data. The camera I used many years ago would often lose track of time and would sometimes be set to the wrong year. Applications I now use to organize photos read this data and made my albums difficult to navigate. I came across a Linux command line utility called jhead that allows you to modify this information to whatever you wish, and its easy to use in scripts as well. Installing was easy, because it’s currently in most repositories, including Ubuntu’s.

To read existing EXIF tag data, simply run jhead against an image without any options. As you can see from the example below, my date is set to the year 2022.

jhead image.jpg File name : image.jpg File size : 159390 bytes File date : 2004:01:12 07:35:23 Camera make : Samsung Camera model : Digimax 200 Date/Time : 2022:02:12 04:04:17 Resolution : 800 x 600 Flash used : Yes Exposure time: 0.045 s (1/22) Aperture : f/2.8

To clear all EXIF data from the file, use the -de option. Then recreate the EXIF fields with the -mkexif option, and check the data again. Notice the new Date/Time is set to the timestamp on the file.

jhead -de image.jpg Modified: image.jpg

jhead -mkexif image.jpg Modified: image.jpg

jhead image.jpg File name : image.jpg File size : 147751 bytes File date : 2004:01:12 07:35:23 Date/Time : 2004:01:12 07:35:23 Resolution : 800 x 600

To change the entire timestamp manually, use the -ts option. Notice, there is no space between the -ts and the option. I could not trust the month and day, so I simply chaged the date to midnight on January 1, 2003.

jhead -ts2003:01:01-00:00:00 image.jpg Modified: image.jpg

jhead image.jpg File name : image.jpg File size : 147751 bytes File date : 2004:01:12 07:35:23 Date/Time : 2003:01:01 00:00:00 Resolution : 800 x 600

For many more options, check out the man page or visit the jhead site for more info.

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Resize and Watermark Images in Linux

gmendoza — Mon, 31 Dec 2007 02:35:13 +0000

If you need to resize and watermark large number of images, there is an easy way to do so using Linux command line tools and a very basic shell script. The easiest and most straight-forward method you can use is through the use of the ImageMagick toolkit. If you don’t have it installed already, you can download it from their site. Most distributions have binaries already built for you. Ubuntu and Debian users can install ImageMagick from the main repositories.

Install ImageMagick

sudo apt-get install imagemagick

Prepare your working environment

Make a directory to store the watermark image (~/Pictures/watermark) and photos you’re working on (~/Pictures/temp). Copy the watermark image and original photos to their respective directories.

mkdir -p ~/Pictures/temp/ mkdir -p ~/Pictures/watermark/ cp /path/to/watermark.jpg ~/Pictures/watermark/ cp /path/to/original-photos/*.jpg ~/Pictures/temp/

ls -l ~/Pictures/watermark/ -rw-r--r-- 1 gmendoza gmendoza 3311 2007-12-30 17:35 watermark.jpg

ls -l ~/Pictures/temp -rw-r--r-- 1 gmendoza gmendoza 885788 2007-12-30 17:35 ubuntu1.jpg -rw-r--r-- 1 gmendoza gmendoza 128922 2007-12-30 17:31 ubuntu2.jpg

Change directories to begin working on your photos.

cd ~/Pictures/temp/

Resizing with “convert”

Let’s say you want to specify a maximum width of 440 pixels (height being adjusted proportionally) in order for you to post the images appropriately within the specifications of your website borders. The syntax would be the following:

convert -resize 440 original-image.jpg new-image.jpg

In this example, we will specify the same name for the output files, which will overwrite the original copies.

convert -resize 440 ubuntu1.jpg ubuntu1.jpg convert -resize 440 ubuntu2.jpg ubuntu2.jpg

Watermark with “composite”

You will probably want to watermark the images after they have been resized, this way there is no distortion of the watermark, and it is appropriately sized. In this example, we will also set the watermark transparency level to 15%, and overwrite the original file again.

composite -gravity northeast -dissolve 15 ../watermark/watermark.jpg \ ubuntu1.jpg ubuntu1.jpg composite -gravity northeast -dissolve 15 ../watermark/watermark.jpg \ ubuntu2.jpg ubuntu2.jpg

Your photos will now have a nice watermark in their upper right hand corners.

Automating the process with a script

You can automate these steps and apply them to a large number of files using a script of course. Feel free to download this one and modify it to your liking.

http://www.savvyadmin.com/downloads/watermark.sh

#!/bin/bash
WATERMARK="$HOME/Pictures/watermark/watermark.jpg"
 
echo "*****************************************"
echo "* Image Resize and Watermarking Script  *"
echo "* By Gilbert Mendoza -  SavvyAdmin.com! *"
echo "*****************************************"
echo " "
 
for each in ~/Pictures/temp/*{.jpg,.jpeg,.png}
 do
  echo "Working on "$each" ..."
  convert -resize 440 "$each" "$each" >> /dev/null
  composite -gravity northeast -dissolve 15.3 $WATERMARK "$each" "$each" >> /dev/null
  echo "... Done!"
 done
exit 0

Additional Options

Please check out the ImageMagick website for more information on the many options and features their products have to offer.

http://www.imagemagick.org/script/command-line-processing.php

http://www.imagemagick.org/script/command-line-options.php

http://www.imagemagick.org/Usage

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