XnViewMP

Powerful if you must have free. Slow with Canon 5DS R RAW files (huge) - make sure to use embedded previews if you don't like beach balling and or hanging apps. If you are simply looking for a tool to rate and review incoming photos before processing, FastRawViewer is inexpensive, powerful, much faster with RAW files and suited to purpose, with a far more Mac-like interface. Extra star for free and trying to bring the IrfanView to the Mac platform. Would not use in production though.

Powerful if you must have free. Slow with Canon 5DS R RAW files (huge) - make sure to use embedded previews if you don't like beach balling and or hanging apps. If you are simply looking for a tool to rate and review incoming photos before processing, FastRawViewer is inexpensive, powerful, much faster with RAW files and suited to purpose, with a far more Mac-like interface. Extra star for free and trying to bring the IrfanView to the Mac platform. Would not use in production though.

Very fast, very efficient, pleasure to use. The interface is not Mac, but that's ok.

love this app.

Awesome lightweight photo organizer. Like Firefox of photo organizer!

I was looking for two specific IrfanView features: renaming and deleting files on the fly through keyboard commands as one leafs through the pictures in a directory, and XnViewMP allows both. Thanks! The interface isn't the easiest to come to grips with at first - I imagine this is the result of cross-platform development. But it didn't take too long to figure out how to do what I wanted, and it has a chock-filled configuration panel which among other things, allows you to assign keyboard short-cuts to what looks like all the features of the program. I still hunger for IrfanView's austerity and speed. This program provides the speed (and the zillions of functions). But this is best I've found so far in the Mac world and ironically it's not a native Mac product! Thank you XnViewMP developers!

Very efficient and fast app for image format conversions, especially batch conversions. The design seems very purpose specific and that is a very good thing. If the requirement is for a general purpose viewer there are other software such as Xee - but this is one of the top performing apps for conversions. Many thanks to the dev. Hoping that the development continues.

I'll probably try this out on my Lion machine, but FWIW it doesn't launch on 10.6.8 - indicates an architecture incompatibility (icon with circle-bar).

Very good and very promising app. Did not crash once. Easy to use. Extremely fast, even when TimeMachine is performing a backup (which I didn't even notice) Great work! Thanks. However, I cannot drag & drop images from the browser to a photo editor. And unfortunately the keyboard shortcuts for enlarge/resize while in fullscreen mode do not work for me.