Which function word to use when using multiple verbs

Using the verbs in separate sentences:

I upload images to the website.

I download images from the website.

(I'm referring to to and from as the function words).

Which function word do I use when using the two different kinds of verbs together?

I upload and download images <which function word here?> the website.

Or should I not be combining them, and instead separate them with an and?

I upload images to the website and download images from the website.

That's correct, but too wordy.

You're talking about prepositions, and you can't use a single one if it doesn't apply to both verbs.

In the example sentence, using a conjunction is correct, but the following is the most succinct way of phrasing it:

I upload and download images to and from the website.

In such a construction, a parallel structure is maintained.

Another option is to rephrase it to use a different verb and preposition, as well as a set of nouns:

I transfer images between the website and my computer.