From our side we recommend the following clients:
- Android: Conversations (€ 2,39 from Google Play or free of charge from F-Droid)
- iOS: ChatSecure (from App Store)
- Linux (desktop): Gajim with plugins "HttpUpload" and "Url image preview"
- Linux (console): mcabber or Profanity
- macOS: Adium
- Web (Browser): Converse.js
- Windows: Gajim with plugins "HttpUpload" and "Url image preview"
There is a more detailed overview here.