Image failed to upload to gallery

Anyone else having trouble uploading images to galleries? Mine are the correct file type, correctly named, under 1MB, etc. and they keep "failing to upload". They then show up in the gallery as an empty box with the file name in the upper lefthand corner.

Is this a squarespace bug??

Don't switch tabs while uploading to design or something else because  the upload will fail.  If the internet is slow don't upload more than one at a time.