Earlier this year we looked at Voralent’s JPGMini and PNGMini, easy-to-use tools which reduced JPG and PNG file sizes without affecting image quality.

The developer has now released a replacement, Antelope, which handles JPG and PNG files, and supports both lossless and lossy compression.

One immediate flaw with the program is that it overwrites your source files by default. Ideally, always work with copies. Otherwise, open the Options dialog and check “Backup original file” before you start.

Once you understand that key detail, basic operation is easy – just drag and drop your images onto the Antelope window and click Compress. The program then uses the open source programs OptiPNG and JPEGTran to apply lossless compression to your images, reporting any file size reductions as it works. Results vary depending on your source images, but will typically just be a few percentage points.

Any savings in file size are immediately displayed as the program works

PNG compression can sometimes be improved by setting Antelope’s “Optimization Factor” to “Max”. It also means the process will take much longer, though – a very large photo might require a minute or more on underpowered hardware – so if you try this, test it with one or two images first.

Antelope now also provides separate “Lossy Mode” options for both PNG and JPGs. Check the appropriate box and the program reduces JPG quality settings and cuts PNGs to 256 colours for major reductions in file size (our test PNGs routinely fell by 60% or more).

You don’t get any control over just how lossy the program should be, unfortunately (there’s no JPEG quality setting), so the best you can do is try it and see. But PNG results in particular are better than you’d expect, with smart palette choices and dithering maintaining surprisingly high image quality. Even high resolution photos may still be usable after being compressed.

Antelope needs work. It really shouldn’t overwrite source files by default, and users require more control over what’s happening. It does provide some effective compression options, though, and as long as you remember to work with copies only, it’s worth a closer look.