muesliI don't really know a client I'm afraid, but what you can do is install a browser extension that lets you pick a mobile user-agent. You can then use their mobile website to upload photos.
Bobinas P4G is a social network. It runs on GNU social, version 2.0.1-beta0, available under the GNU Affero General Public License.
All Bobinas P4G content and data are available under the Creative Commons Attribution 3.0 license.