We've never supported copying+pasting directly into the web browser. However, we do support drag-and-drop file uploads, which means you can always drag and drop a file off of your desktop. But if you want to drag-and-drop a file directly from another program, it depends on how that other program has implemented the feature. I can do it from Skitch, for example, but whether or not it will work directly from another web browser page depends on the browser. Dragging it from the web browser directly onto desktop, and then dragging it from the desktop into Roll20 should always work. I can say that we have't made any modifications at all to the way that our file uploading works in a long, long time, so if there was behavior before that isn't working now unfortunately it's probably due to a change in the way that the other program is handling their drag and drop functionality, not anything on our end. I will take a look and see if I can get it working in Chrome by changing how it works on our end, but this is one of those "we don't have any direct control over it" situations.
