Image plugin should not execute if there's an text/html payload in the data

[tiberiuichim]

Copy/pasting from Excel puts an image and also a table in the data. The image plugin should look for this and (maybe optional) not insert an image in the content, but leave the table to be inserted.
Alternatively, it could insert the image but also leave the table, so the editor gets a chance to choose which version s/he prefers.

[tiberiuichim]

Maybe show a preview? "It looks like you're importing rich content, what would you like to have, an image or separate blocks" ?