When you’re creating web graphics then it’s important to keep file sizes small, as that will cut page download times and reduce your bandwidth requirements. And you probably do this already by reducing an image’s pixel size, complexity, colour depth and more.

But if you use PNG files then you might also want to try PNGGauntlet, which compresses files to make them more efficient. Savings can be as much as 50%, yet there’s no loss in image quality – each picture should look exactly the same.

The program is essentially a front end for three open-source image optimisation tools – PNGOUT, OptiPNG and DeflOpt – which means it gets to apply a host of low-level trickery on each of your files. It might strip out metadata, for instance, optimise palettes, minimise bit depth (where it won’t affect the image), and more.

Drop images onto the program, click "Optimize!" and see how much the files shrink

But while PNGGauntlet provides access to the settings for each tool, for those who are interested (click Tools > Options), you don’t have to get involved with these technicalities at all.

And in fact the core program operations really couldn’t be much more straightforward. Just drag and drop your target images onto PNGGauntlet, choose an output folder, click “Optimize!” and wait to see how much you’ve saved.

Does it work? We found some large logo files online, expecting these to be a difficult test as they would presumably have been fairly well optimised already. But actually PNGGauntlet still performed very well. One file was reduced from 71.63KB to 39.44KB in size (a 44% drop); others were cut by 24%, 20% and 7%, and even the best compressed two were still reduced in size by a few bytes.

There is a small question about whether these size gains are really penalty-free. We’ve seen suggestions that in a few, rare cases, they can leave PNG images not rendering properly on a few mobile browsers, for instance. This isn’t an issue we’ve experienced ourselves, but if you do decide to upgrade your website with PNGGauntlet-processed graphics then we’d recommend you test the pages carefully, just to make sure that everything looks exactly as it did.

If PNGGauntlet really can cut images by 20% or more, though, that’s obviously going to deliver major benefits in website performance and bandwidth use. Go grab a copy of the program, see what it can do for you.