max-image-preview

What the rule says

"Set the maximum size of an image preview for this page in search results. If you don't specify the max-image-preview rule, Google may show an image preview of the default size."

The values are documented one line each:

Two things follow from the default. First, doing nothing is not the same as standard: Google says it may show a preview "of the default size", which it does not define here. Second, this rule is the only one on the page that governs image size, so nothing else you set will change it.

The clause that is missing

This is the reason the entry is worth reading. max-snippet and max-image-preview stand directly beneath one another in the documentation, are written to the same pattern, and differ at exactly one point.

max-snippet says the rule applies to "all forms of search results (such as Google web search, Google Images, Discover, Assistant, AI Overviews, AI Mode)" and adds that it "will also limit how much of the content may be used as a direct input for AI Overviews and AI Mode".

max-image-preview says:

"This applies to all forms of search results (such as Google web search, Google Images, Discover, Assistant)."

The list stops there, and no second clause about direct input follows.

We counted rather than assumed. "AI Overviews" appears four times on that documentation page, twice inside the definition of nosnippet and twice inside the definition of max-snippet. None of the four is in this section.

Read that for what it is. Google does not say this rule affects images used in AI answers, and it does not say it has no effect either. Anyone presenting max-image-preview:none as an AI measure is filling a gap in the documentation with an assumption.

It is the rule that removes the thumbnail nosnippet leaves

nosnippet stops the text snippet and the video preview, and then adds a sentence people find surprising: "A static image thumbnail (if available) may still be visible, when it results in a better user experience."

If a bare result is the actual goal, nosnippet alone does not deliver it. max-image-preview:none is the rule that addresses the image, and the two work on different things rather than reinforcing each other.

The same holds one step further along. max-video-preview:0 is documented as allowing "at most, a static image […] in accordance to the max-image-preview setting", so the video rule hands the decision back to this one.

The permission door

The same carve-out that sits in max-snippet sits here, and it is worth quoting because it names a case most publishers do not think of as permission:

"However, this limit does not apply in cases where a publisher has separately granted permission for use of content. For instance, if the publisher supplies content in the form of in-page structured data (such as AMP and canonical versions of an article) or has a license agreement with Google, this setting will not interrupt those more specific permitted uses."

Google then says what to do about it:

"If you don't want Google to use larger thumbnail images when their AMP pages and canonical version of an article are shown in Search or Discover, specify a max-image-preview value of standard or none."

So the limit has a door in it, and the instruction for closing that door is to set the same rule with a smaller value. Setting large and publishing article structured data are two ways of saying the same thing to Google, and only one of them is visible in your .

What to do with it

Decide it once, site-wide, and know which value you chose. The default is undefined in the documentation, so "we never set it" is not a known state.

Pair it with nosnippet if a bare result is the goal. One rule handles text and video, this one handles the image.

Do not sell it as an AI control. The documentation attaches that effect to nosnippet and max-snippet, and stops the list short here.

Check your article structured data before assuming a limit holds. It counts as permission granted separately.

Remember the video rule defers to this one. max-video-preview:0 still permits a static image at whatever size this rule allows.