As you may know, XnConvert is a free image convertion tool, developed by the XnSoft team (the creators of the XnViewMP app). It has support for the most popular image formats, including: JPG, PNG, TIFF, GIF, BMP, RAW, PSD, JPEG and OpenEXR.
Because of its basic image manipulation functions, it allows the user to easily modify the opacity or the color of the photos, add filters or different effects to the photos. The application excels at converting multiple images simultaneously.
The latest version available is XnConvert 1.7.2, which has been recently released.
Installation instructions:
In order to install XnConvert on Ubuntu 16.04 Xenial Xerus, Ubuntu 15.10 Wily Werewolf, Ubuntu 14.04 Trusty Tahr, Linux Mint 17.x and Elementary OS 0.3 Freya you have to add the PPA to your system, update the local repository index and install the xnconvert package:
$ sudo add-apt-repository ppa:dhor/myway
$ sudo apt-get update
$ sudo apt-get install xnconvert
For Debian, LMDE and Debian-based systems, you can download the deb packages from the project’s and install them by hand. I prefer gdebi over dpkg due to the fact that it also handles dependencies.
How to install XnConvert on 32 bit Ubuntu, Debian and derivatives:
$ sudo apt-get install gdebi
$ wget http://download.xnview.com/XnConvert-linux.deb
$ sudo gdebi XnConvert-linux.deb
How to install XnConvert on 64 bit bit Ubuntu, Debian and derivatives:
$ sudo apt-get install gdebi
$ wget http://download.xnview.com/XnConvert-linux-x64.deb
$ sudo gdebi XnConvert-linux-x64.deb
Optional, to remove xnconvert, do:
$ sudo apt-get remove xnconvert