As and when the username for a user is changed, the user's corresponding profile picture also changes automatically. In case the user justs wants to change her username she would have to re-upload her profile picture back again unless she selects her current profile picture from the right every time before changing the username.
Moreover, if an existing username is typed, that user's profile picture appears. Only a message saying "Username already exists" would suffice without changing the profile picture.
The profile picture remains the same and only the username changes. If an already taken username is entered, the profile picture of that user shouldn't appear.
The profile picture changes as and when the username changes. On clicking "Save Changes" the changed profile picture appears.

Can I work on this issue?
Sir, Should the suggestion avatar image change with the change in the username or it should also be fixed.
Looks like it may be addressed in Rocket.Chat 3.10. Noted that the default avatar changes letter (not colour) as appropriate only after saving, and custom avatars are left intact.
https://github.com/RocketChat/Rocket.Chat/pull/19805 - For reference
Looks like it may be addressed in Rocket.Chat 3.10. Noted that the default avatar changes letter (not colour) as appropriate only after saving, and custom avatars are left intact.
Ok Got it
Please Review My fix https://github.com/RocketChat/Rocket.Chat/pull/19991
I believe the Default avatar "suggestion" should always show the color and letter changing, but the actual profile pic should only change when one of the buttons is clicked.
Most helpful comment
I believe the Default avatar "suggestion" should always show the color and letter changing, but the actual profile pic should only change when one of the buttons is clicked.