In a rather ironic way, the free and exquisite image manipulation suite from
http://imagemagick.org/ provides a GUI for me to do just about everything the suite
can do via the separate utilities included, but for the Windows build, the GUI is merely a displayer. For myself the separate commands are more elegantly invoked directly anyway, so that's how I do it: the same way a Windows user would
have to. Usually the Windows user will consider having to use a command prompt a very great imposition (which it in fact is compared to a
real command interpreter the likes of which MS doesn't offer, but that's a separate matter since the good stuff is also freely available in Windows builds).
In the example above it was nothing more than the equivalent of issuing the command at the prompt:
<font class="small">Code:</font><hr /><pre>convert -quality 75 original.jpg modified.jpg [enter]</pre><hr />working in the directory which contained "original.jpg". The result was a still-unmodified "original.jpg" and a shiny new "modified.jpg" alongside it. Nothing could be easier. Literally. Even when using a GUI one still must type in a target file name, and using the mouse merely becomes an added inconvenience requiring a hand-shift to the keyboard and back again, and again, and again.
There may be a Windows-centric utility which does provide most of the same functionality, but I'm not a Windows user and am not familiar with what's out there for it.
Fetch the ImageMagick package you need and holler if you need a hand with it.
Glen