Pasting some html tables and… mess

Hi all,
I searched the forum but I have not found the answer I am looking for.

I have edited in an html editor a 13×8 table with only some background images for the cells and some links. Columns and rows have specific width and height inputs. That’s all.

When I try to copy and paste the html code in a new wordpress page the result is a mess. If I try to copy in the WYSIWYG editor is even worse, of course.

It doesn’t respect the height-width parameters, the image in the background is replicated in each cell…

Does anybody have any idea of what I can do?

Thanks in advance.