It seems to be something related to the memory consumption during the resize process. In fact I’ve tried to resize the images to 1024x*** before uploading in the directory of the gallery and then to import them doing a rescan of the directory and it worked. Let me know if it is the same for you.
I have the same error. The strange thing is this didn’t happen a week ago. Anyone have found a way to get rid of this error? Changing the browser didn’t work for me.