The Images should be uploaded to the Images/Upload folder.
make sure this folder has the appropriate Read, write permissions for all users. This can sometimes be done using Dreamweaver.
In the files panel, select Remote View, expand the images folder and right click on the Upload folder, select Set Permissions. Make sure Write is selected for Owner , user and Everyone.If you cannot do this using Dreamweaver, you may need to use third party FTP client.