RAW image conversion software

[MIDI01]

Is there any alternatives I can use to DarkTable and RawTherapee. For some reason the exported png images are much larger than the raw NEF images. Even on Darktables compression level 9 they seem to bloated in size. For some reason the Raw NEF file for one is 24 but the export of a png 8 bit with compression level 9 ends up as a huge 39 Mb size file.

I don't think I can upload files that huge when sharing to public domain image sites. Is anyone here well veresed with image formats? How does png hold up these days?
edit: Even a webp 8-bit lossless ended up bigger than the original NEF raw image at 30.3 Mbs

 

[KGIII]

I haven't tried it with RAW files, but use it otherwise.

Take a look at XnViewMP (formerly just XnView, and formerly just for Windows). It's available for Linux as well, which makes me pretty happy. You should be able to convert and even compress.

They also have an XnConvert that now works with Linux - which might be able to do all sorts of stuff with RAW files, including making them smaller in batch processes.

Image Viewer | Photo Viewer | Image Resize | XnView

XnView, one of the best and popular image viewer

www.xnview.com

They're free for home use but not free as in open source. I'm a pretty big fan but have a much more limited use case than you have.