Hi there,
I've exactly the same problem and it's not linked to the web browser I use (tryed IE 9 and 10, Firefox and Chrome). In fact, here is what I've noticed.
The drag and drop feature works for the web part and list applications. I can easily add a file to shared documents for example.
I'm creating a new Wiki page in my Wiki web part, in Sharepoint Foundation 2013. Then, I begin to write some text and I want to add a picture. I'm doing then a drag & drop operation to insert the picture from my local hard drive. In the first place,
the picture is normally displayed on my page layout, but at the time I save my work, the image disappear !
And if I go check the raw source code, I see an empty img tag : <img alt=""/> surrounded with <p> tag. So it creates the structure but doesn't upload the file, nor add the link src.
The only way I found to display pictures so far was using Sharepoint Designer, and uploading manually my images, then on the top ribbon : Insert > Picture > From an address and pasting the image url in the field. It's slow and uneffective, please could
someone provide me a hint or some help ?
Thanks in advance.