Image size checker:Which images make your page heavy?
See every image on your page with its file size, format, real and displayed dimensions, and which ones are too heavy, too big or missing width and height.
- Free, no account
- Results in under a minute
- Up to 100 images per page
example-shop.hr
WordPress 6.8Sample shop · homepage · mobile Chrome · the same check you get for your own site
5 passed · 1 failed · 3 warnings. Biggest issue: 15 images have no alt attribute.
Detected technology
- WordPress 6.8
- WooCommerce
- Elementor
- jQuery 1.12.4
- LiteSpeed
Images on this page
4 images · 1830 KB total| Image | Size | Format | Pixels | Displayed | Loading | Status |
|---|---|---|---|---|---|---|
| example-shop.hr/assets/hero-large.pngno alt | 1829 KB | png | 1200×520 | not set | eager | 200 |
| example-shop.hr/assets/img-300x300.pngno alt | 1 KB | png | 300×300 | not set | eager | 200 |
| example-shop.hr/assets/img-160x40.pngno alt | 1 KB | png | 160×40 | 160×40 | eager | 200 |
| example-shop.hr/assets/img-100x30.pngno alt | 1 KB | png | 100×30 | not set | eager | 200 |
What we found
Show 5 passed checks
Fix these first
From the example above. Check your own site to get the fixes that apply to it.
Problem: 15 images have no alt attribute
Alt text is how Google Images and screen readers understand a picture.
How to fix it: Describe each meaningful image in a short alt attribute ("Blue running shoe, side view").Warning: 4 images weigh 1831 KB (largest 1829 KB)
Images are usually the heaviest part of a page.
How to fix it: Resize images to the size they are shown at (a 400 px wide photo does not need a 4000 px file).Warning: 1 image is larger than 300 KB
A single image over a few hundred kilobytes takes longer to download on mobile than the rest of the page.
How to fix it: Export each listed image at the size it is displayed and save it as WebP or AVIF at about 80 % quality.
What this tool checks
Each image measured from the file itself, plus the total image weight the browser loads.
Heavy image files
Finds single images that are too large in file size and slow the page down on mobile.
Oversized images
Finds images served at more than twice their displayed size, which wastes visitors' data.
Images without width and height
Finds images without width and height, which make the text jump as the page loads.
Broken images
Finds images that fail to load and leave an empty space or placeholder for every visitor.
Total image weight
Adds up the size of all images on the page, usually the heaviest part and slowest on mobile.
Images without alt text
Finds images with no alt text, which Google Images and screen readers need to understand them.
Modern image formats
Checks images use WebP or AVIF, which are much smaller than JPEG and PNG at the same quality.
Image sizing
Finds images sent larger than the space they are shown in, wasting bytes on every visit.
Offscreen image loading
Checks images below the fold wait until scrolled to, so the visible ones load first.
Show 5 more checks
Total image weight
Adds up the size of all images on the page, usually the heaviest part and slowest on mobile.
Images without alt text
Finds images with no alt text, which Google Images and screen readers need to understand them.
Modern image formats
Checks images use WebP or AVIF, which are much smaller than JPEG and PNG at the same quality.
Image sizing
Finds images sent larger than the space they are shown in, wasting bytes on every visit.
Offscreen image loading
Checks images below the fold wait until scrolled to, so the visible ones load first.
How it works
Read each image
Up to 100 image sources are requested. The first 64 KB of each gives its format and pixel size, and Content-Length gives its file size.
Compare with the HTML
Using the width, height, loading and srcset attributes, we flag files over 300 KB, images over twice their displayed size, missing dimensions and failed loads.
Load the page in Chromium
Chromium loads the page without scrolling, so the total image weight includes CSS backgrounds, and Lighthouse adds its format and sizing estimates.
The per-image table lists <img> tags found in the HTML. CSS backgrounds and images added by scripts count in the total but get no row of their own.
Questions
Is this really free?
Yes. getReport is funded by donations, not plans. This tool runs the full report and shows you the part it is about; the complete report with all seven modules is one click away, also free.
What size should an image be?
At most twice the width it is displayed at (for high-density screens), in WebP or AVIF at about 80 % quality. A 400-pixel product thumbnail needs an 800-pixel file at most, usually well under 60 KB.
Why is the total in the report higher than the table?
The table lists <img> tags found in the HTML. The total from Chromium also counts CSS background images, favicons and images added by scripts.
Does it check images in CSS or behind a lazy-load script?
data-src and srcset attributes are read, so most lazy-load plugins are covered. CSS backgrounds show up in the Chromium total but not in the per-image table.
Do you store my results?
The report is kept for 12 months at its shareable link so you can come back to it. Reports are not listed publicly and carry a noindex tag; nothing about your visitors is collected.
Why do image sizes matter?
Images are most of the bytes on most pages. One original camera file in the hero can weigh more than everything else together and decides the Largest Contentful Paint on its own. Resizing to the displayed width and exporting as WebP or AVIF usually cuts a page by half without a visible change. Width and height attributes are the other half: without them the text jumps as images arrive and Cumulative Layout Shift suffers. They cost nothing to add.
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