Raw Therapee’s de-mosaicing algorithms reduce artefacts in converted images, and its multi-core support makes full use of your available hardware.
Once you’re happy with the fruits of your labor, you can save the settings as a preset for future use.
Unfortunately, although it's a superb app for mobile devices, Google Photos doesn't offer the same processing power as the Picasa desktop software.
There's no batch processing and editing is quite basic, so it's slipped down our rankings to number five.
Raw files contain all the data captured by your camera’s sensor, and all camera manufacturers have their own format for storing it.
Irfan View combines a powerful image editor and organizer, with excellent support for raw and compressed file formats (see the full list).
They also offer tools for cropping and rotating images, but if you’re looking for retouching and healing tools, you’re better off with a free Photoshop alternative.
Raw Therapee is an advanced open source Lightroom alternative for processing raw files (or compressed image files like TIFF and JPG), then sending the resulting images directly to GIMP (or your preferred photo editor).
Its interface isn’t as intuitive as some other free Lightroom alternatives, but it’s been in development for 20 years and is packed with thoughtfully designed tools for photographers of all abilities.
Irfan View is one of the best free tools around for cataloging images – editing metadata, renaming files in batches, and adding tags – enabling you to get huge image libraries under control in the space of an afternoon.