Your profile picture and name come across from your Alpha Universe profile. So head to https://alphauniverse.com/ and log in, then press on your name in the top right hand corner and a drop down menu will appear. If you press on edit profile, you'll be able to update your display name and profile picture there! Let me know if you need any further assistance.
We don't have galleries implemented on the forums yet, but you can upload photos directly to your posts here! When you make a post you can drag and drop photos into your post, or click "choose files" to add them to your post that way.
If you mean on your Alpha Universe profile - once you're logged in, press on your name in the top right and then press "edit profile" and scroll down to Gallery and you can upload up to 25 images.
Universe
