You can simply apply a custom watermark to all your images, which are in your uploads folder. This plugin renders the watermark on-demand on your images, i.e. no data is altered and the watermark is also rendered on already uploaded images. You can find the settings under: Settings/Dynamic Watermark Main Features: Custom watermark Transparency is supported (alpha channel) Enable/disable watermarking No images are altered Watermark already uploaded images Here are some requirements to run the plugin (most of the time no problem): Mod_rewrite module installed Write permission for uploads folder