Yes, of course! As the owner of the picdrop account, you can set the language in your account settings: User Data & Password
If you work with clients who speak other languages, simply send them the link to your gallery as usual. As soon as your clients use a non-German-language computer, the gallery will automatically be displayed in the language that best suits them. You don’t have to do anything. Currently, picdrop supports the following languages: German, English, Spanish, Italian, and French.
If you want to be on the safe side, you can also set the language permanently in your gallery settings, and your customers will then always see the galleries in the language you set, no matter what computer or browser they’re using.