Recently we took a look at PNGGauntlet, an excellent tool which could compress PNG files by up to 50% without any apparent loss of quality.

If you found that program useful, but wished it had more scope, then you might want to take a look at FileOptimizer. This tool can compress images, documents, archives, audio files, executable files, 33 formats in total: AIR, APK, APNG APPX, BMP, CBZ, DOCX, DLL, EPUB, EXE, GIF, GZ, ICO, JAR, JPEG, MNG, MP3, MPP, PNG, PPTX, ODT, OGG, OGV, PDF, PUB, SCR, SWF, TIF, VSD, WEBP, XAP, XLSX, and ZIP.

And of course in every case the aim is for the compressed files to behave exactly like the originals. So if you try to shrink some PDF files, for instance, they should look the same: the only difference will be a reduction in size.

Unsurprisingly, FileOptimizer can’t achieve this magic without a little help. The program is essentially a front end for a host of other tools. Present it with a PDF file, say, and behind the scenes it’ll call up Ghostscript to do the actual optimisation.

The simple interface displays the percentage you've shaved off each file's size

This does at least make for very easy operation, though. To use FileOptimizer you just drag and drop your target files onto the program; right-click, select Optimize, and watch as the files are processed, and their “before” and “after” sizes displayed.

Does it work? Sometimes. Our test images shrank by up to 50%; even some JPEGs dropped by 20% or more; we managed to reduce one PDF file by 54%, and most of our test ZIP files could be trimmed by a percentage point or two.

But, on several occasions the process went disastrously wrong, corrupting rather than compressing the source. This only happened a few times, and only ever with the more complex file types – EXE, PDF – but that’s obviously still a few times too many.

Worse still, FileOptimizer replaces the source files with its processed versions, while the originals are sent to the Recycle Bin. You can restore these with a click or two, of course, but if you get distracted with some other task then it’s at least possible that you might forget, then empty the Bin and lose them.

Don’t let this put you off entirely. If nothing else, FileOptimizer makes a great image compression tool. We achieved great results with GIFs, JPEGs and PNG files, and had no file corruption issues at all.

Just be careful if you want to compress more complex file types. Always work with copies of your files, rather than the originals, and check the compressed versions carefully to make sure that they behave exactly like the source files.