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Resize Image to 350kb

Full-bleed hero image dragging down your load time? Bring it to 350kb and the page paints faster without losing its punch. Free, no signup, nothing uploaded.

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Supports JPG, JPEG, PNG, WEBP, HEIC formats

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How It Works

Step-by-step guide to resize image to 350kb to exact specifications

Upload The Hero Or Banner Image

Drag in a JPG, PNG, WebP, or HEIC export of your hero image or landing-page banner. Multiple banner variants — desktop, mobile, section headers — can be loaded together.

Set The Size Target To 350kb

Dial the target to 350kb. If the page layout needs specific pixel dimensions for the hero slot, crop to match first so the compressed file drops straight into the design.

Preview And Ship

Check the compressed banner against the original in the preview, confirm it sits under 350kb, then download and drop it into the page. Nothing was uploaded during the process.

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Why Choose Imresizer?

Fast, secure, and completely free image resizing

  • Compresses Locally, Not On A Server

    The banner is processed entirely inside your browser, so nothing is transmitted anywhere. Handy when you're compressing unreleased marketing creative or a client's pre-launch landing page assets.

  • Lands At 350kb, Not A Byte More

    Enter 350kb as the target and the tool works backward from that number, so the finished banner sits right at the ceiling instead of guessing with a quality slider and re-exporting three times.

  • Sized For Page-Speed Scores

    Hero images are usually the largest single asset on a landing page and a common culprit in a failing Largest Contentful Paint score. Reduce image to 350kb and the biggest asset on the page stops being the bottleneck.

  • Cuts Real Load Time

    A 350kb hero loads in a fraction of the time a multi-megabyte export takes, which matters most on mobile connections where every extra second of load time costs conversions.

  • Faster First Paint On Every Device

    Smaller banner files mean the browser can render above-the-fold content sooner, so visitors see something meaningful before they've even finished scrolling into the page.

  • Batch Every Banner Variant Together

    Landing pages often need a desktop hero, a mobile hero, and a handful of section banners. Load them all at once and compress every variant to 350kb in a single pass instead of handling each separately.

  • Preview The Result Before Shipping

    See the compressed banner next to the original with the exact file size shown, so you can confirm text overlays and product shots still read clearly before it goes live on the page.

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Frequently Asked Questions

Everything you need to know about image resizing

How do I shrink a hero image to 350kb?

Upload the banner, set the target to 350kb, and the compressor does the rest automatically. Compare the preview against the original before downloading to confirm text and product shots still read clearly.

Why do landing pages need hero banners under 350kb?

The hero image is typically the largest asset above the fold, and page-speed tools weight it heavily in metrics like Largest Contentful Paint. Keeping it around 350kb helps a landing page load quickly enough to satisfy Core Web Vitals thresholds without visibly compromising the banner.

Will compressing a banner to 350kb make text overlays blurry?

Sharp text and clean edges generally hold up well at 350kb since compression targets smooth gradients and fine photographic detail first. The preview shows exactly how any overlaid text looks before you save, so you can catch a problem before it ships.

Can I compress multiple hero variants to 350kb at once?

Yes — load a desktop hero, a mobile hero, and any section banners together and reduce them all to 350kb in one batch. Faster than exporting and compressing each size separately.

Does this tool upload my marketing images anywhere?

No, compression happens entirely in your browser on your own device. That's useful when the banner is unreleased creative or a client's landing page assets that haven't gone live yet.

Is it free to resize a banner to 350kb?

Yes, fully free with no account required and no watermark added. Compress as many hero images and banners as your site needs, with no daily limit.

What formats work for a 350kb hero image?

JPG works best for photographic hero shots since it compresses efficiently at this size. WebP often produces an even smaller result for the same visual quality if your site supports it. PNG is better reserved for banners with flat colors, logos, or crisp typography rather than full photos.

Do a desktop hero, a mobile hero, and a footer banner all fit in one 350kb batch?

Yes. Different banner sizes for different breakpoints can be loaded together and each gets compressed toward 350kb independently within the same batch run.

How do I keep a hero image sharp while getting it under 350kb?

Export at the actual pixel dimensions the hero slot displays rather than a much larger master file — feeding in an oversized image just forces heavier compression to reach 350kb. Starting near the display size preserves more visible sharpness.

What if my banner is already smaller than 350kb?

Then it's already page-speed friendly and there's nothing more to do — upload it as-is. The tool won't add weight to a file that's already under the target.

Can I compress a landing-page banner from my phone or tablet?

Yes, it works in any modern mobile browser. Select the image from your device, compress it to 350kb, and the finished file saves locally, ready to upload to your CMS.

How does image size at 350kb affect a Core Web Vitals score?

A lighter hero image speeds up Largest Contentful Paint, one of the three Core Web Vitals metrics Google uses to judge page experience. Trimming the biggest image on the page to around 350kb is often the single fastest way to move that score from failing to passing.
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