Best Lossless Image Size Reduction Freewares

Lossless image reduction means reducing a given image's size without losing quality at all!

This should be done by default, the truth is that we shouldn't have external tools to reduce size without losing anything because the current software we use to create the original images should apply lossless image reduction techniques - it is lossless so no quality is lost what so ever!

Anyway, we live in a non perfect world, so we need these tools.

In my post i want to write about the best tools for this task.

Requirements:
1. Lossless image size reduction.

2. Support for all file formats (at least png, gif & jpg).

3. Easy to use user interface.

4. Option to be recursive = option to submit to the tool a directory and it will convert all of the images it contains (and all of the images contained in any sub directory etc)

5. Option to overwrite original images.
6. Free

After lots of googling around I found the following as the best tools to use, please note that I am cutting to the chase and give you my conclusions only without exposing lots of the information I gathered and without giving you the less attractive alternatives:

I actually found two great tools which won in all categories:
1. ScriptCX (Works from explorer context menu)
2. FileOptimizer  (but note that I think that it removes all image metadata if not configured to sustain it).

These freewares are maintained well and have constant releases, support lots of file formats by using many small open source libraries, have a nice user interface (or a simple explorer context menu) and provide the best file lossless compression I could find.

Choose either one or just use both.
I choose to stick with the ScriptCX because of the simple context menu (right click on a directory), and it is much much faster than fileOptimizer but I suggest keeping an open eye on both projects.

I would also consider "Jpeg & Png Stripper" for the basic use of stripping only the metadata recursively on a parent directory (although, when using the FileOptimizer customized to remove metadata, then this tool won't add much).

I want to also recommend a great blog post with thorough comparison between many pieces of software as a good read - if you want a second opinion  :-)

Please note that my findings are relevant to the date I wrote this post which is 27/09/2013 - in a later date someone might release a better piece of software  :-)