PNG is an excellent graphics format which can achieve very good compression rates. We’ve regularly covered tools which can optimise them still further, though – including PNGOptimizer, just last month – and PNGmini is the latest contender.

The program installs easily (no adware), and looks great. There’s a sleek, black interface, flat buttons, red status bar and highlighting, while menus slide out smoothly with a click. It manages to be modern, without simply copying anything else.

PNGmini isn’t as impressive in terms of features and functionality, though, because it has almost nothing at all. There’s no “Add” button to import files, so you must drag and drop them onto the program. There are no options or settings to consider. All you get is an Optimize button which rewrites each file, trying to save space, before displaying the results.

PNGmini looks great, but it’s distinctly short on configuration options.

This simplicity is certainly appealing, but it does have one important consequence. You don’t get to choose an output folder, or decide how the rewritten PNG files will be named: PNGmini always overwrites the original files.

To be clear: PNGmini always overwrites your original files. This shouldn’t be a major issue – the worst that’s likely to happen is they won’t be reduced in size – but just in case of problems, you should always work with copies.

What results can you expect? We ran PNGmini through our two standard PNG compression tests.

First, we passed it 100 web graphics taken from real websites, and it reduced their size by 20.04%. That’s disappointing, as tools like File Optimizer and PngGauntlet achieve around 40% here.

Our second test uses 25 HD photos, 200MB of data. This is much tougher, but the program still cut them down by 4.22%, comparable with – or even fractionally ahead of – the market leaders.

PNGmini desperately needs at least an option to avoid overwriting its source images. And there’s clearly significant work to be done on its compression engine. Still, this is only version 1.0, and if you’re looking to compress larger images then the program may already deliver useful results. Just be sure you always work with copies of your source files.