XnView Software

Hello All - a wee query which I have searched for a solution to no avail.
I have a hard drive of many folders at root level (with each also containing sub folders) containing tiffs which I want to use XnConvert to convert into jpgs. This which works perfectly well for individual files and an individual folders. When selecting 'folder' during Input, there is no way to 'select all' or select more then one folder, unless I'm missing a quick key combination.
Is this a limitation of the program which means I will need to spend ages doing one folder at a time?
Will I need to somehow copy/move all 6Tb of the files into 1 root folder?
Appreciate anyones input here to save my frustration and looking for another program to do this.
Cheers
Rab

Well....
Been trying a few things and looks like there is a round about way to do this:
At INPUT select 'Add Folder' as usual and then select 'Add Folder' for the next one and continue until all the folders your needing to convert are 'ADDED'.
I find it can take a long time for the files in the folders to be recognised in the Input Box, so I after a few minutes I just click 'CONVERT' button bottom right and it trundles away doing the conversion.
I've only been selecting a handful of folders to convert at a time as unsure if there is a file limit restriction on what XnConvert can handle?
(Perhaps someone can reassure me on this???)

I'm not sure to what extent if any XnConvert processes folders recursively, but I see on the Output tab there is an option Keep folder structure, and a sub-option Keep parent folder which look promising...

Always test with copies of files!