Cannot upload any images

I can no longer use Drag& Drop upload on image fields to upload images. The automatic upload option and the manual upload options are not working in any browser. If I drag or browse to an image the thumbnail version appears as normal, but no upload occurs. If I change the field widget to "image" I can upload an image as part of node/add.

I have been troubleshooting a different issue with uploading files as part of field collections this week. I don't think there is a relationship between the two issues, but I have been making changes such as re-checking my file permissions on my default/files directory. Everything seems to be set correctly, and as I mentioned, if I change the widget to "image" from Drag & Drop I can upload an image and have it appear on the node without incident.

Not sure if this is related to the issue I started recently on the last of a multiple set of images not uploading?