Adding multiple images uploaded via FTP to existing category

[rodedo]

Maybe my question is trivial, but I did not get it reading through documentation and all my attempts did not achieve the expected result.
I have a set of subfolders under PhocaGallery directory, each one contains the image files of a distinct category (I do not use subcategories).
I uploaded the images with their folder structure using FTP and then I used the multiple add (images->multiple add->select all folders->do not select any category->save and close) to have PhocaGallery create all categories and import all images. Afterwards, I manually adjusted all category's names and settings as I required.
Now, what I would like to do is to add multiple images to one of these existing categories by first uploading the files to the right folder via FTP. After FTP upload, I can add these images one at a time (images->new->select category->select appropriate folder->add appropriate new file->save and close), but how can I add all - and only! - the new images at once to the category (i.e. import them in the DB)?
I tried with: images->multiple add->select the folders which contains new files->do not select any category->save and close, but I got a new category with all images of that folder; with: images->multiple add->select the folders which contains new files->select target category->save and close, but I got a new subcategory with all images of that folder; with: images->multiple add->select target category->multiple upload->Add files, it asks me to upload the files but they are already there.
Could someone indicate me step-by-step the right way to achieve what I need?

[Jan]

Hi, yes, unfortunatelly, the folder must have the same name as category to use update category at once. If it is different, then only the option is to select new added images and add them to selected category.

Jan