How To Check If Your Website Has Heavy Images (Free Google Tool Guide)

I am curious, have you ever checked why your website is getting slower day by day? The majority of you guys won’t, right? What if I told you that, your site is too slow because of the heavy images you use! Yes, you may ignore image sizes but, a 5MB image looks the same as a 50KB one, but it will kill your website speed. That’s true!

According to the sources, in late 2025, Google’s Core Web Vitals are stricter than ever about large files. So, not underestimating it is a safe way to stand out in this field.

Google has its own tool to check website speed called Pagespeed Insights. It’s an official tool by Google and mainly, it’s free to use. 

This article is going to be a practical guide where I’ll teach you step by step about these things:

• How to scan your website in 2 minutes
• And mainly, how to spot heavy images that are slowing down your site and 
• How to fix those heavy images properly! So, let’s get started. 

Step 1: Open Google Pagespeed Insights (Free Tool)

The tool Pagespeed Insights is officially built by Google to check site performance, speed, accessibility and SEO score for websites.

Now, go to pagespeed.web.dev. First, enter your website URL in the search box of pagespeed insights and then click the Analyse button. It may take up to 10-20 seconds to load & process and after that, the health report of your site is in front of you. 

Step 2: Look for the “Opportunities” Section

Once the report of your site loads, scroll down and find the section called ‘Opportunities.’ This is the section where Google list all those things that are hurting and slowing down your website. 

Usually the major problems are indicated in red and orange triangles, and this is what we are gonna solve today and improve your site speed. 

Step 3: Spot the “Serve Images in Next-Gen Formats” Warning

Find the warning section called “serve images in next-gen format” (it should be indicated as red). If you can’t see it, Great. But if you can see it, it’s a clear warning! 

Usually this error comes when you use old and heavy image formats like JPG and PNG directly in your website. 

If you can see the ‘serve images in next-gen format’ error, it’s a negative signal from Google especially for images! Google is literally telling you to stop using JPG/JPEG images because they are destroying your website speed, and use WebP instead.

To identify those exact heavy images, click the down arrow on that warning and you’ll get the list of all those heavy size images. It also shows how much exact space you could save from converting them to WebP (e.g., “Potential Savings: 2.5s”).

Step 4: Check for “Properly Size Images” (Optional but Helpful)

Sometimes you cannot see the “serve images in next-gen format” error, instead it may show a different one like “Properly Size Images.” In this case, you are using images in a correct format but, image dimensions are way too big for the screen (like a 4000px wide image on a mobile phone). 

A solution for this error, is to resize your images properly and convert them to WebP format. You will always get a resize images option while converting to WebP! If not in other converters, you can use our JPG to WebP Converter. 

For normal website use, Google recommends to maintain a image dimensions (or width) below 1600 pixels. It’s ideally about 1200×1200 px for square images, and 1200×628 px for landscape images. 

How to Fix These Errors Quickly?

The first rule, to solve a problem, first understand that problem! The exact reasons behind these errors are wrong image format and improper dimensions. Don’t worry, you don’t need to hire a developer to do this! Instead, you can solve it by yourself. Just follow these steps. 

Convert them safely to WebP format 

You now have the list of all those heavy images, right? Now let’s safely convert them to WebP. 

1. Open our Safe WebP Converter and select your JPG images by clicking Browse Files button. 
2. After selecting, you’ll find some pre-built presets for best practices. Choose it according to your use cases, or you can adjust it manually too.
3. Then simply press the Convert button. 

Good news, all of your images are safely converted to WebP after following this simple steps! 

Use Proper Image Dimensions 

To readjust image dimensions, 

• Open our Safe WebP Converter. 
• Select images by clicking Browse Files button.
• After selecting, click on Show Advanced Options (below presets).
• You can see the resize images option. Check that!
• After checking, our tool suggests the best dimensions but, you can still enter your preferred one, no problem! 
• Done, all of your images are safely converted to WebP with proper dimensions. 

By doing this, you will satisfy Google to turn that red warning into green, and speed up your site.

Pro Tip: Converting all existing JPGs in your website to WebP will effectively increase your website speed. 

Why Google Loves WebP

WebP is a modern image format developed by Google, to improve website speed and performance. Basically WebP holds the same image quality with up to 50% smaller file size compared to JPG and PNG.

Google recommends WebP because it,

• Reduces server load on our site (because it’s smaller & better).
• Loads faster & improves user experience. 
• Improves page loading speed. 
• Improves core web vitals metrics. 
• Helps in better rankings, etc.

To know more about WebP, check out our article What is WebP and How it Improves SEO. 

FAQs 

Conclusion 

In conclusion, I would like to say, taking action is way better than just thinking! 

Guessing will waste a lot of time, as it did for me when I was a beginner. You decided to increase your website speed, right? Then don’t guess, just do it! 

Your major steps now should be, go to pagespeed insights and check for heavy images. And fix them by converting it to WebP and by readjusting its width or dimensions. 

Go check your site now, then come back to our converter to fix it for free and mainly in a safe way! 

Have a Great Day!