You can upload your photos directly to your galleries through your Studio Panel.
Inside any Gallery, click the "Add Photos" button to upload photos. On the next screen, you can drag and drop or click to browse your computer for the files you'd like to upload.
On this screen, you can also choose which watermark you'd like to include on the photos, as well as choose an Album (if any) that you'd like the photos loaded into. You can also set the web-based uploader to allow duplicate files to be uploaded. If you keep this setting turned off, any files with the same name as photos already in the Gallery will NOT be uploaded.