In Linux, I actually migrated from using the Firefox icon
on the desktop to Konqueror which is the native browser
in Linux. The reason for this is the way that Konqueror
is more closely integrated to the KDE desktop-- the desktop
of preference for many users. This has to do with how
Linux reads fonts. What this means is that there is less of
the control ++ activities to enlarge or shrink the display
fonts on web pages.

Linux has several desktop environments: KDE and also Gnome.

Regardless of the desktop or the distibution you select,
Firefox is in the taskbar for easy use.

As to ISOs: I've had good success downloaded ISOs in
the download procedure in Firefox under Windows and also
using Firefox download under a Linux distro called
Simply Mempis.

Burning the ISO an uncomplicated procedure if you observe
the steps... I have the steps in the link below.

Once the ISO is burned to cd or dvd depending on the size,
the disk is ready to either run (live Cd) or install to a
hard disk.

Mepis has an install routine on their Live CD disk.

• How to burn an ISO in Nero and Nero Express