You must be in 4 images administrator to do this. "Add Categories" in the admin control panel to create your categories. DO NOT USE FTP to create new directories. This is very important since the directories where images and thumbnails are to be stored is automatically created by 4images when the category is created. Once created, go to "Edit Categories" and move your mouse over a specific category in the list into which you want to upload new images. Your browser status bar will display a URL for the category. At the end of this url will be "?cat_id=" and a number. Like this for a example (http://yourSite/gallery/categories.php?cat_id=47) Make a note of this number (In this case the number would be 47)as it corresponds to the directory name used by that category for storing images and thumbnails. Now open FTP go to where you have your 4 images files and go to /data/media/ look through all your categories till you find the number you need (in this case 47) then upload your images to to this folder. You can also upload your thumbnails to 4images/data/thumbnails/<number>( IN THIS CASE 47) category. In order to get 4images to pick up your thumbnails, they must have the exact same file names as your images. But I personally like to use the auto-thumbnailer to create the thumbnails for you instead of uploading my own while I am in the control panel.