When uploading the image/document from the web content portlet, which already exist, then it shows the the message "Upload a new file in this folder (Upload in progress, please wait...)".
It doesn't show any message like, Image/Document Already exist or Image/Document already uploaded. It just showing the upload in progress.
Steps to Reproduce:
1) Add a image in document library through the control panel
2) Add web content display portlet on a page
3) Edit WCD portlet and select "image" icon to upload an image
4) Select the image that was uploaded in the document library through the control panel
5) Save portlet
6) Edit the portlet
7) Select the image icon and this time select the option to upload a document to the same location as the file that was added in the control panel
8) The status of the upload will read: (Upload in progress, please wait...)and you will receive stack trace like the one I have uploaded
That the editor would display something along the lines of "Image/Document Already exist or Image/Document already uploaded".