update nunber of images per row

I created some galleries and now i change my mind, so i want e.g. 5 images per row. For new galleries works fine, but the old ones does not updated. I tried also by deleting the thumbnails with no luck.
I'm doing something wrong?

Maybe your images folder is not writable? If not CHMOD it to be 777 (writable).
Easiest way to check and do this is by using joomlaexplorer (just google that).

Hardi, it's maybe doesn't show 5 images in a row because you don't have enough space/width in your template to show that much images.

Thanks Milan and ivan for your response.
Actualy Ivan, I'working this project at the moment localy with WampServer. Besides, the problem occurs when i try to change the number of rows. Not when i create a gallery from scratch.
Milos, yes. 5 images fits. Besides, as i said, the problem occurs when i try to change the number of rows. Not when i create a gallery from scratch.

On server it is 755. Is it safe to change it? And if i do it, i have to change thw whole path, or just thw specific one?

you can change it temporarily.