If you have any add-ons/customisations which increase the sizes of avatars used then this customisation is the cause.
If it relies on a template modification or similar then this may no longer being applied if we have made any changes to that template. You would need to seek assistance from the author of that customisation.
The avatar in your screenshot is the "large" size avatar; I can tell because of its original aspect ratio rather than being square. We don't use that size avatar anywhere apart from member card and user profile.
I don't know why I can't remember any changes related to this.
Its was right, and Today I just upgraded my XFRM and XF and XFMG. No more changes.
Even when I change it now, it has the problem again:
Would you mind letting me know where could be the problem please?
The issue is now resolved, but really it must have been something down to your style.
The exact issue is there wasn't an appropriate "left-margin" for the user info container property.
I've changed this for you and it now looks normal across the gallery and forum.
I have reverted back to using the medium avatars so you may wish to look at re-enabling the large ones again. Hopefully you won't see any issues, but if you do this is definitely the kind of thing you would need to contact the style author about.
I really didn't know it is something with my style.
Also developer of my style that is also developer of one of my important add-on is not really active nowadays and he supports really really slowly (and sometime its better to say no appropriate support)