A picture is not reserved for something we can see with bare eyes - an infrared camera produces a photo, we don't call that an illustration - such cameras are used in military, geology, earth mapping and agriculture, etc. Most images in industry and astronomy could never be seen with bare eyes, because our eyes can see only 1% of what our instruments can.

Ofcourse each wavelength of light works a bit differently, like with the X-ray example, you need to understand how X-ray works to understand what you are looking at.

A model or illustration is something that would be product of our calculation or imagination, that was given visual form.

I agree that in science, as we extend our perception with instruments, it's difficult draw the line between an image and an illustration or diagram.

I'm maybe grumpy because this relatively featureless image of relatively massaged data is presented by mainstream news as "FANTASTIC new photo of a Black Hole! WOW! It looks just like in Interstellar!"

But our “bare eyes” are, too, merely instruments that the brain receives signals from; these signals have an electro-chemical nature, and in the brain they have to pass through a number of layers of interpretation before they reach the consciousness.