What can't you describe without a picture?

There is a phrase "beyond words", but it is not usually used for objects, more for emotions or situations.

Oops, logic has just given me a good kick - if there was a word for such objects, then such objects would cease to fall into this category. ;-)

Of course, there are words like "thing", "nondescript", "thingamajig", "visual", "spectacle", "sensory" and "picturesque", and phrases like "to be seen".

A pretty word for things that cannot be expressed in words is ineffable, but if it's describable with a picture, it doesn't feel ineffable. Unless you're talking about qualia. An example would be helpful.

Well, I suppose I would call them indescribable.