>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3595073. --> Reported by: [tim bozeman](https://www.drupal.org/user/2241356) >>> <h3 id="summary-problem-motivation">Problem/Motivation</h3> <p>AI image generation (the <code>_generate</code> syntax on media reference fields) ran whenever the AI requested it, with no way to turn it off. A site could not disable it short of removing the field handler, and an individual editor could not opt out, so every request spent a <code>text_to_image</code> (Imagen) provider call even when the user only wanted layout or text changes.</p> <p>Generated images also had no shape control: every image used the provider's default aspect ratio regardless of whether it was a full-width hero or a square thumbnail. Finally, the generation write path created media and wrote fields without checking the browsing user's access.</p> <h3 id="summary-proposed-resolution">Proposed resolution</h3> <ul> <li>Add <code>ImageGenerationGate</code>, which ANDs a site-wide master switch (<code>ai_plus.settings.image_generation_enabled</code>, default on) with a per-user preference (navigation_plus <code>EditorSettings</code>, key <code>ai_plus.generate_images</code>, default on). Generation runs only when both are on.</li> <li>When generation is off, the field handler keeps the placeholder (on create) or the existing value (on update) as the final image and emits no <code>DeferredOperation</code>. It returns a <code>BlueprintWarning</code> so the AI tells the user generation was off and how to re-enable it. Remediation differs by level: a site-wide switch needs an administrator, a per-user toggle the editor can flip themselves.</li> <li>The <code>_generate</code> syntax gains an optional <code>aspect_ratio</code> (<code>1:1</code> / <code>4:3</code> / <code>16:9</code>), validated by the handler and honoured by the processor, including across the prompt-rewrite retry.</li> <li>Gate the write path on the current user: media create access before spending an Imagen call (non-retryable on denial), and field-editable access before each layout-surgery write.</li> </ul> <h3 id="summary-ui-changes">User interface changes</h3> <ul> <li>New <strong>Enable AI image generation</strong> checkbox on the Navigation Plus settings form (the site-wide master switch).</li> <li>New per-user <strong>Generate images</strong> toggle in the AI tool's Edit Mode settings panel, shown only when generation is enabled site-wide and persisted live via the navigation_plus editor-preference helper.</li> <li>The "generating" shimmer now highlights the specific field being generated rather than the whole block.</li> </ul> <h3 id="summary-api-changes">API changes</h3> <ul> <li>New service <code>ai_plus.image_generation_gate</code> (<code>ImageGenerationGate</code>).</li> <li>The <code>_generate</code> field-handler guidance now documents the optional <code>aspect_ratio</code> and how to choose it.</li> <li>Relies on entity_blueprint's <code>BlueprintWarning</code> (returned when generation is off) and <code>BlueprintAccessChecker</code> (write-path access checks), and navigation_plus <code>EditorSettings</code> (per-user preference).</li> </ul> <h3 id="summary-data-model-changes">Data model changes</h3> <ul> <li>New config key <code>ai_plus.settings.image_generation_enabled</code> (boolean, default <code>true</code>), with matching config schema.</li> </ul>