I have both (even paid for Fast Stone) but I've ended up using XnView MP instead, as it currently offers just a little more. You can (as with Fast Stone) assign a keyboard shortcut to open the selected file in any one of several programs, so the viewer can function as a dispatcher of sorts. However, I agree with others that I use a better bitmap editor for anything above trivial stuff. There's also XnView MP which has star ratings and color tagging, basic editing tools (levels, curves, etc.), runs on Linux / Windows / Mac and is free. Then, see those grades in Lightroom and do my editing and exporting there. My current Lightroom workflow is star images as Delete - 0 Star - 1 star - 2 Star as a first round, so to be able to quickly view the RAW (or jpeg) images in FastStone and grade them in a way Lightroom can see is all I need. My thought would be to use it strictly to view the images, not to edit. You can display the RAW data but no colors or optics corrections applied so not at all a Raw converterīut still very usefull, I am mainly using it to compare different versions of tiffs coming from my true RAW processors also to cull initially my new RAW pictures and send them to my true RAW processors, by launching à program or by copy Paste to an open one Yes Faststone very fast very usefull to cull ,compare classified directly from your foldersīy défaut it display the jpg embedded, not always the same resolution as the raw data,

But I don't care, because a jpeg is just fine for culling (seeing if a portrait subject's eyes are closed, etc). When I click on a raw image n FastStone, I have no idea if I am seeing the converted raw data or the embedded jpg. It is free, So why not just try it for yourself. But I love it for culling because it displays the image full screen and it is my default viewer when I click on an image attached to an email, etc. But I prefer more advanced (paid) software as an editor.

I have used this software solely as an image viewer for 15-20 years.

Faststone free