Got 3 upload failures in a row trying to upload GIF files. Didn't try any JPEGs but if you were wondering about the notifications thats what its about.
HHHmm.... I'll take a look at it. There might be something a little screwy yet from the server move.
EDIT: OK, likes like it may have been an ownership issue when moving between the servers. On the old server the files & folders were owned by user X but on the new box they are owned by user Y; I reset the permissions & ownerships and everything seems to be up & running again.