I have noticed some items I had imported starting to not show up in my search functions and looked at the main import list in my vault and noticed they were missing. There being some kind of import limit is understandable, I would guess by counting it’s 143 items, or 13 rows of 8. I would assume it deleted the oldest imported items first but I’ve yet to test it out exactly for that.
I’ve been creating my houses for a town a piece at a time in their own maps then exported the finished product to get around some of the large map size issues and to speed up the process of creating multiple similar buildings. This led to me having a rather large import section and I noticed this.
If this is the limit I would only suggest having some kind of notification telling you the limit 1/143 or something and perhaps have a pop up warning a user that they reached their limit when trying to import a file. This could either have them being forced to choose a file to delete themselves first, or still going with the oldest but at least they would know before hand. It would really suck to lose something you imported a year ago and no longer have because of this feature for people who don’t import many pictures.