I have experimented a bit with Riot.im, and have found that with the Android Riot.im app on the matrix.org instance, images can be exchanged successfully. In principle, I could switch to this service, and try to persuade everyone that I currently communicate with on Wire to follow me to a Matrix-based service. I do not see this as a solution though: the administrators of matrix.org (or other Matrix instances) could drop support for older versions of TLS and I would then be in the same situation as I am now with Wire.