October3
All pictures taken with digital cameras add information to images they take. A lot of information. To see it, install imagemagick using this command on the command line..
sudo apt-get install imagemagick
Then, just use the identify command thus..
identify -verbose /home/me/pics/some_picture.jpg
and it should pump out a heap of data.
Personally, if ever uploading photos to the internet (never) or emailing them to friends (rarely), I make sure to strip all the data from them. For this, use mogrify, also from the imagemagick suite…
mogrify -strip /home/me/pics/some_picture.jpg
Now the exif data has been removed. Nice!

September5
Sometimes you need to take a pic of a document say, and then put it into a pdf. Here’s how. In Linux.
You’ll need the awesome imagemagick package first. To install it, use..
sudo apt-get install imagemagick
Once that’s in, open a terminal window. Navigate to the folder you have the images in and then just run the command…
convert the_image.jpg the_document.pdf
Got multiple JPGs and need to squeeze all the images into the same pdf?
convert *.jpg the_document.pdf
Need to reduce the images to 1024 pixels across by whatever down and strip out meta data in the JPG files first though? Fer security and confidentiality?
mogrify -strip -resize 1024x *.JPG
“Nice one centurion, Like it.”