Google Ads AI Video Generation & Resizing in 2026: What PMax Advertisers Must Know Now

What is Google Ads' new AI video ad generation and resizing feature?

The key change is that Google Ads is now applying generative AI directly to Performance Max (PMax) video ads to automatically create multiple aspect ratios from a single uploaded video. This means a 16:9 horizontal video can be reformatted into vertical (9:16), square (1:1), and other sizes without manual editing. The goal is to let a single creative asset serve across YouTube, Discover, Gmail, and the Google Display Network, eliminating a long-standing pain point for advertisers who had to produce separate assets for each placement.

Google introduced this capability in mid-August 2026, with an official announcement covered by Search Engine Land. The company is using its proprietary generative AI models to analyze the original video content, identify key subjects, and recompose frames for different aspect ratios while preserving the core message and branding. Advertisers have until September 4, 2026, to opt out if they prefer to provide their own custom-sized videos.

This builds on a broader trend: just over a week later, on August 25, 2026, Google brought its advanced Gemini Omni model into Asset Studio within Google Ads, as reported by Search Engine Land. Gemini Omni goes beyond resizing—it can generate entirely new multi-format videos from creative briefs, brand guidelines, and existing assets, dramatically shortening the production pipeline for video ad campaigns.

How does the PMax video resizing work?

The PMax resizing feature is automated by default. When an advertiser uploads a video to a Performance Max campaign, Google's AI analyzes the content and produces additional aspect ratios. According to Search Engine Watch, the system optimizes for "viewing experience" and "maximizing reach" by ensuring the ad fits the screen of whatever device or platform a user is on.

Aspect	Details
Automation level	Fully automated; runs on all new and existing PMax video ads by default
Opt-out deadline	September 4, 2026
Supported formats	Landscape (16:9), portrait (9:16), square (1:1) — possibly more
Control	Advertisers can disable resizing per campaign or asset group
Creative sources	Uses original uploaded video content as input

The AI is not creating new scenes or generating synthetic video from scratch (in the resizing case—the Gemini Omni tool does). Instead, it is intelligently cropping, recomposing, and sometimes regenerating background elements to fit different frames. Google has not detailed the exact model architecture, but the results suggest a diffusion-based approach trained on millions of ad creatives.

What is Gemini Omni video creation in Google Ads?

Gemini Omni is a separate, more powerful feature integrated into Asset Studio. As Search Engine Land described on August 25, this tool allows advertisers to input creative briefs, brand guidelines, logos, and existing assets, and receive fully produced video ads in multiple formats. Unlike the resizing tool, which only modifies existing footage, Gemini Omni can generate entirely new video sequences, including voiceovers, transitions, and product demonstrations.

The feature represents a significant leap from earlier AI ad tools, which were largely limited to writing headlines or suggesting images. With Gemini Omni, a brand could input "30-second video ad for winter boots targeting outdoor enthusiasts" along with product shots and a brand color palette, and the system would produce several candidate videos ready for campaign deployment.

Why is Google doing this now?

Google faces increasing competition from platforms like TikTok, Meta, and Amazon, which have aggressively rolled out AI creative tools. Meanwhile, Performance Max has become Google's flagship campaign type, dominating ad spend for ecommerce and lead generation. To keep PMax competitive, Google needs to remove friction in creative production. Manual video resizing is a well-documented bottleneck—agencies and in-house teams frequently report spending hours on format adaptation. By automating this, Google reduces the barrier to entry for video advertising and potentially increases its own ad revenue as more campaigns launch with video assets.

There is also a strategic push toward full automation. Google CEO Sundar Pichai has stated that AI will "reimagine advertising." These video tools are the latest step in that direction, following earlier AI features like automatically generated headlines and responsive display ads.

What are the risks for advertisers?

Not all advertisers welcome this shift. The primary concerns fall into three categories:

Brand control and consistency. When an AI crops or recomposes a video, it may center the wrong subject, cut off a logo, or distort brand messaging. A luxury brand, for example, relies on carefully art-directed frames. An auto-cropped version could look cheap or misaligned with brand guidelines. The PPC Geeks UK analysis warned that advertisers must scrutinize ROAS and conduct compliance checks on AI-generated creative, as the risk of brand-damaging outputs is real.

Measurement and attribution. If Google's AI generates multiple versions of a video, which version drove the conversion? Standard attribution models may not track the creative variant, making it harder to optimize. Some advertisers have reported difficulty determining whether a performance lift came from better audience targeting or AI-generated creative changes.

Compliance and legal exposure. In regulated industries (finance, healthcare, gambling), every ad frame must undergo compliance review. An AI that creates new aspect ratios or entirely new videos introduces uncounted variants that may violate regulatory requirements. Advertisers in the UK and EU face particularly stringent rules from the Advertising Standards Authority (ASA) and GDPR, and the PPC Geeks UK piece explicitly flags this as a critical issue.

How do UK and EU advertisers need to prepare?

For UK advertisers, the issues are particularly acute. The ASA requires that claims in ads be substantiated and that ads not mislead consumers. An AI-generated resized video might accidentally omit a disclaimer or crop out a required small-print warning. As PPC Geeks UK notes, the first commercial risk is "compliance — your AI-generated video might not be compliant with advertising standards."

Additionally, under GDPR, automated decision-making that produces creative variations without human review could raise data protection questions if personal data is involved in targeting. Advertisers should:

• Audit every AI-generated variant before it goes live.
• Disable auto-applied creatives using the opt-out process before September 4.
• Maintain a manual review workflow for any Gemini Omni-generated content.
• Consult legal teams about the implications of AI-generated creative in regulated sectors.

Should you opt out by September 4?

The deadline is September 4, 2026. Google has stated that advertisers can opt out per campaign or asset group, but the default is enabled. The lumienai.com report emphasizes that this is "a significant product launch" that requires careful consideration.

Factor	Opt Out Recommended	Opt In Acceptable
Regulated industry (finance, health, pharma)	Strongly recommended	Only with strict manual review
Luxury or premium brand with strict visual identity	Strongly recommended	Only if brand guidelines are strict
Performance-first brand with high creative volume	Consider testing on non-critical campaigns	Worth trying for reach expansion
Small team with limited creative resources	Can test on low-risk campaigns	Likely beneficial to save time

For most advertisers, the prudent approach is to opt out immediately, review how the AI performs on test campaigns, and then selectively opt back in where results are positive.

Best practices for using AI video ads in Google Ads

Advertisers who choose to use these tools should follow a structured approach:

1. Test on low-budget campaigns first. Don't let AI resize your biggest-spending PMax campaign before you understand the creative quality.
2. Set up creative tracking. Use Google Ads' asset reporting and custom labels to identify which video variant is performing.
3. Establish a human review loop. Have a creative director or brand manager approve all AI-generated variants before launch.
4. Monitor frequency and overlap. Multiple aspect ratios can increase frequency for the same user across different placements, potentially leading to ad fatigue.
5. Combine with structured prompts. As Practical Ecommerce suggests, well-crafted prompts can significantly improve AI-generated ad quality.
6. Leverage first-party data. AI-generated creative works best when fed with high-quality brand assets, product images, and customer insights.

The broader landscape: AI-generated ads across platforms

Google is not alone in pushing AI-generated ad creative. Meta's Advantage+ creative tools, TikTok's AI Video Generator, and Amazon's image-to-video feature for Sponsored Brands are all battling for advertiser attention. In some cases, the rush to AI has produced controversy. Channel NewsAsia recently reported that sellers on Shopee and TikTok have called out auto-generated AI ads that mislead customers, highlighting the trust deficit that can arise when AI creates advertising without sufficient human oversight.

This context matters for Google Ads users. The technology is powerful, but the responsibility for accurate, compliant, and brand-safe creative remains with the advertiser. Google provides the tools and the opt-out mechanism, but it does not assume liability for AI-generated content that violates laws or platform policies.

What does this mean for Performance Max strategy?

Performance Max was already Google's most automated campaign type. Adding AI video resizing and generation deepens that automation, making PMax more of a black box. Advertisers must decide how much control they are willing to trade for efficiency.

For ecommerce brands using PMax for product catalogs, the AI video features could be transformative. Instead of filming 20 product demos in different formats, a brand can upload one video and let Google handle the rest. However, for brand-building campaigns where every frame is deliberate, the trade-off may not be worth it.

The Search Engine Land and Search Engine Watch reports both emphasize that Google sees this as an improvement in "viewing experience" and "reach." But advertisers who have tested early versions report mixed results: some see CTR improvements of 10-20% from better-fitting formats, while others see brand recall decline because the AI cropped out key visual elements.

How to opt out of AI video resizing

The opt-out process is straightforward but time-sensitive. Advertisers must act before September 4, 2026. To opt out:

1. Go to your Google Ads account.
2. Navigate to the Performance Max campaign settings.
3. Look for the "Creative asset optimization" or "Video resizing" toggle.
4. Disable the feature for each campaign or asset group.
5. Confirm the change.

Google has not yet stated whether the opt-out can be applied globally or only per campaign. Multiple sources, including Search Engine Land, recommend checking each active PMax campaign individually.

The bottom line

Google's AI video ad generation and resizing features represent a genuine leap forward in ad creative efficiency. For many advertisers, the ability to deploy video across every placement without manual resizing will save hours per campaign. But the automation comes with real risks: brand inconsistency, compliance exposure, and reduced creative control. The September 4 opt-out deadline is not a suggestion; it is a hard cutoff. Advertisers who do not act will find their carefully crafted videos being recomposed by AI, for better or worse.

The smartest strategy is to test deliberately, measure rigorously, and never assume the AI understands your brand as well as you do.