The little list when I want to @mention someone - for the past few weeks, shows most with the usual tiny thumbnail.
But the odd ‘random’ one as a larger circular image.
For example @muha… (on iNat itself, not here in the forum)
Shows only https://www.inaturalist.org/people/meaw101 as a large circle. In a new tab the profile picture is about twice the size of the next one.
https://www.inaturalist.org/people/muhammad_a shows the expected tiny thumbnail.
There must be a reason why iNat displays The One with a larger image.
Also Chrome