Il telefono visualizza tutte le foto.

In Italian, nouns are very often used with an article where English might omit it less often.
So il telefono means the phone.

• il = the for a singular masculine noun
• telefono = phone

You could say just telefono in some special contexts, like labels, headlines, or notes, but in a normal sentence il telefono is the standard form.

Il is the singular masculine definite article used before most masculine singular nouns beginning with a consonant.

Here:

• telefono is singular
• telefono is masculine
• it begins with t, a consonant

So the correct article is il: il telefono.

Visualizza comes from the verb visualizzare.

In this sentence, it means something like:

• displays
• shows
• brings up on the screen

With technology, visualizzare is very common for screens, phones, apps, computers, and menus.

So Il telefono visualizza tutte le foto means the phone is displaying or showing all the photos.

Not always. This is an important point.

In English, to visualize often means to imagine mentally.
In Italian, visualizzare very often means to display on a screen.

So in a tech context:

• Il telefono visualizza le foto = The phone displays the photos

It usually does not mean the phone is mentally imagining them.

Because this is the third-person singular present form of visualizzare.

The subject is il telefono, which is it in English.
So:

• io visualizzo = I display
• tu visualizzi = you display
• lui/lei visualizza = he/she/it displays

Since il telefono = it, the verb must be visualizza.

Because foto is a feminine plural noun.

The word tutto must agree with the noun:

• tutto = masculine singular
• tutta = feminine singular
• tutti = masculine plural
• tutte = feminine plural

Since foto is feminine plural, you need tutte:

• tutte le foto = all the photos

Good question. Foto is short for fotografia, which is feminine.
So even though it ends in -o, it is still feminine:

• la foto = the photo
• le foto = the photos

This is one of those words you simply need to learn as an exception in form, though its history explains why.

In Italian, when tutto means all before a noun, it usually comes with a definite article.

So:

• tutte le foto = all the photos
• tutti i libri = all the books
• tutta la casa = the whole house

Without the article, the structure usually changes meaning or becomes unnatural here.

So tutte le foto is the normal way to say all the photos.

Here it most naturally means all the photos.

Italian often uses:

• tutte le foto = all the photos
• ogni foto = every photo / each photo

Both can be similar in meaning depending on context, but they are not identical in structure.

So in this sentence, tutte le foto is the straightforward equivalent of all the photos.

The normal word order is:

• Il telefono = subject
• visualizza = verb
• tutte le foto = object

So this is a standard subject + verb + object sentence.

Italian word order can sometimes change for emphasis, but this version is the most neutral and natural one.

For example, Tutte le foto le visualizza il telefono would sound marked or emphatic, not like the ordinary default sentence.

A helpful approximate pronunciation is:

vee-zwah-LEET-tsa

A few useful points:

• vi sounds like vee
• sua blends into something like zwah
• -lizza has a ts sound because of zz
• the stress falls on -liz-

So: vi-sua-LIZ-za

Because Italian usually does not need subject pronouns when the subject is already clear.

Instead of saying it displays, Italian simply says:

• Il telefono visualizza...

The noun il telefono already tells you who or what is doing the action.

Even when the subject is a pronoun, Italian often leaves it out:

• Visualizza tutte le foto = It displays all the photos / He/she displays all the photos, depending on context

Yes. Mostrare means to show, and in many contexts it works well:

• Il telefono mostra tutte le foto

That sounds natural too.
However, visualizza is especially common in technical or screen-related contexts, where display is a better match in English.

So:

• mostra = more general shows
• visualizza = more technical displays/shows on screen