Can I change image conversion settings when, for instance, converting a BMP image to JPEG? Changes like image quality for best compression or best quality or use optimized Huffman codes when encoding. Or you just click the convert icon and DO chooses what it thinks is best?
You can control the JPEG quality and also whether or not JPEG rotation is lossless (for zero quality loss) or causes a re-compression (e.g. if you want to reduce the file size and rotate at the same time), and a couple of other things.
The JPEG quality can be set interactively, or via arguments to the Image command. Lossless rotation is done by default and can be turned off via the NOLOSSLESS argument to the Image command. The manual included in 10.0.1.6 beta has the full details and lots of examples in the Reference / Command Reference / Internal Commands section.
As far as I know, there isn't an option to enable/disable optimized Huffman codes. (I'm not sure what that means in this context, though. It's possible it is tied into the quality setting but, either way, there isn't an explicit, independent option for it.)
Thanks for the answer. I use PicaView 2.0 to convert images and do other things. To this day I haven't found a replacement (XnView doesn't work that well) for this software and no matter what I do it won't install in my Win 7 x64 (not even on Win XP SP3 virtual machine). But from now on DO will serve me well.
Hopefully the built-in image conversion features will do everything you need. They cover the most common tasks. But, if you do need something more advanced, ImageMagick is a free, excellent tool which can do almost anything to images and which is easily integrated into Opus.