A built in viewer handling many different file types including pdf, jpg, avi etc would be really good - FreeCommander has this ;)
If you view a picture it will be open by the picture viewer.. however pdf and video are not supported, mostly because I have not had the to investigate if some free 3d party libraries that can be used (Because there is no way I get the time to write it myself.). It might be added if I get the time.
One way might be to look at the methods (or even use directly) Universal Viewer.
http://www.uvviewsoft.com/
Custom External Viewers and Editors for different filetypes can be configured under Configuration > File Type Setup
Sorry, I didn't mean external viewers - I meant an internal viewer like the Quick View Panel you get with other commander clones such as Total Commander and FreeCommander which usually toggle with the Ctrl-Q key stroke.
You mean a preview panel that are inside a tab ?
Well that is totally different thing. something like that is on my todo list..
Yup, that is exactly what I meant. Great to hear it's on the to do list!