Re InfoQube (IQ):
I'm a fairly basic user and am not familiar with any other comparable apps - but I'll chance a comment.
It's essentially a two pane outliner/database.
Grid/Outline (text, with html formatting possible) and the HTML pane, which contains rich-text/html + images (related to the items in the grid).
Drag n drop does not work the way you want it but
There are other methods:
- Win+C - very easy
copies selected text [& images] directly to the html pane (via a new item dialogue), title of window is used for the grid text, and the url is saved. By default it goes to an inbox grid but this can be changed from the dialogue, or later. - there's an extension for FF & IE so I can copy selected text or full pages via context menu or a button.
If you can live without the drag n drop aspect, all you other requirements are met.
Caveats might be that it's still is in Beta, the interface need work to make it more friendly. Some people do have difficulty at the beginning with it.
OTOH there is documentation which may be imperfect but is being improved all the time. You'll always get help quickly at the forum
http://www.sqlnotes..../index.php?q=tracker. I've been using IQ for years for work stuff without losing anything and what with it being in development it's been updated a lot. It's portable too

[edit] download link (go for the portable version)
http://www.infoqube.biz/downloadand 'help' page here on dc
InfoQube (IQ) Information Management System Q & A [/edit]
edit2/ minor, in [square brackets]