Configure xfce4-screenshooter settings

xfce4-screenshooter is the standard screenshot program in XFCE on Xubuntu.

How can I configure the settings about which format it saves the screenshot in and in which folder?

I noticed, that my settings I made in shutter also affect the settings of xfce4-screenshooter (but not all).

EDIT:
The man page sais, there is an -o option to open it with an external program.

How can I make this default? Then I could set there an external program, that automatically compresses the screenshot to an emailable size

The man page of xfce4-screenshooter mentions some of its options, including this one:

• -s (--save): Directory where the screenshot will be saved

To save to a fixed screenshot directory, go to Setting Manager -> Keyboard -> Application Shortcuts and click Add command. Add this command:

xfce4-screenshooter -s ~/screenshots

Assign it to any key you like, like PrtScr.

PNG is the only output format possible for now, but you could write a script that converts the screenshots automatically to JPG every time you take a screenshot:

#!/bin/bash
mkdir -p ~/screenshots
xfce4-screenshooter -fs ~/screenshots
cd ~/screenshots
mogrify -format jpg *.png

Save the script as shoot.sh and assign a shortcut key (CTRL+PrtScr works fine). The command to enter is sh shoot.sh. If you don't need the PNG files and you only want JPG files, you can add

rm *.png

to the script.

E-mail integration with Thunderbird:

#!/bin/bash
SCREENSHOTS=~/screenshots
mkdir -p $SCREENSHOTS
cd $SCREENSHOTS

xfce4-screenshooter -fs $SCREENSHOTS
SCREENSHOTPNG=`find . -type f -mmin -1`
SCREENSHOTPNG=`basename $SCREENSHOTPNG`
mogrify -format jpg $SCREENSHOTPNG
#uncomment the line below (remove the #) for even smaller files (and comment the line above):
#mogrify -resize 50% -format jpg $SCREENSHOTPNG
rm $SCREENSHOTPNG

SCREENSHOTJPG=`find . -type f -mmin -1`
SCREENSHOTJPG=`basename $SCREENSHOTJPG`
thunderbird --compose "attachment=$SCREENSHOTS/$SCREENSHOTJPG"

Thunderbird supports more default fields, see all parameters here.

Important Mogrify is part of ImageMagick, so you need to have ImageMagick installed. On Ubuntu, you can install it with sudo apt-get install imagemagick

The suggestion from @Smile4ever to just pick a different folder is fine, but unfortunately -s stops it from then prompting you to run an application on the new image, and you cannot combine this with -o. From this I gleaned that g-get-tmp-dir was being used to pick a directory used with -o, so in order to keep the default behavior of prompting for an application but customize the directory, it seems you need to create a custom script like

#!/bin/bash
export TMPDIR=$HOME/Downloads
exec xfce4-screenshooter -f

in your $PATH and then use that script as the command bound to Print.