The 4000px Photo That Broke My Client's Page
A client called me confused — their new landing page was scoring 34 on PageSpeed. I pulled it up in Lighthouse and saw one culprit immediately: a single hero image at full camera resolution, 4032 × 3024 pixels, displayed at 1200px wide. The browser was loading every single one of those 12 million pixels just to scale it down. I resized to 1400px wide, re-exported, and the score jumped to 79. That was the moment I stopped treating resize as optional.
How to use this resizer
- Upload your JPG, PNG, or WebP (up to 30 files at once).
- Enter a target width, height, or both. Leave one blank to scale proportionally.
- Keep aspect ratio locked to prevent distortion.
- Choose WebP output for smaller files on the web.
- Click Resize and download.
Upload Images
You can also drag and drop files here.
Why I always resize before I compress — in that order
People often reach for the compression slider first because it feels like the obvious knob. But resizing is almost always the bigger win. Cutting a 4000px image down to 800px eliminates 25 times as many pixels — no compression setting gets close to that. My rule is: get the dimensions right first, then use compression to polish what's left.
The sizes I actually use day to day
Over time I've built up a short list of target widths that cover most of what I need. I keep aspect ratio locked and just enter the width:
- 1400px — hero images on most websites. Wide enough for large screens, not wasteful on mobile.
- 800px — blog post body images. Matches the content column on almost every theme I've worked with.
- 1080px — Instagram square posts. Lock to 1080×1080 with aspect ratio unlocked, then let the subject fill the frame.
- 1280px wide, 720px tall — YouTube thumbnails and 16:9 social images. This is my go-to for anything video-adjacent.
- 400px — thumbnail previews in carousels, related post images, anything displayed small.
The aspect ratio lock — when to use it and when not to
I leave it on 95% of the time. It means I only have to think about one dimension — the other scales automatically. The 5% of the time I unlock it is when I need a specific canvas size for a platform that's strict about dimensions, like a LinkedIn banner (1584×396) or a Twitter header (1500×500). If I force both numbers without the lock, the image stretches to fit. That's intentional — the alternative is cropping, which I do separately.
Common social media sizes I reference constantly
| Platform / Use | Dimensions (px) | Aspect Ratio |
|---|---|---|
| Instagram Post (Square) | 1080 × 1080 | 1:1 |
| Instagram Portrait | 1080 × 1350 | 4:5 |
| Instagram Story / Reel | 1080 × 1920 | 9:16 |
| YouTube Thumbnail | 1280 × 720 | 16:9 |
| Facebook Cover Photo | 820 × 312 | ~2.63:1 |
| Facebook Post | 1200 × 630 | ~1.91:1 |
| X (Twitter) Post | 1200 × 675 | 16:9 |
| LinkedIn Post | 1200 × 627 | ~1.91:1 |
Files processed privately — deleted on completion
Your images upload over HTTPS and are processed in temporary storage. Both the original and the resized output are deleted automatically when the job completes. No account required.
Frequently Asked Questions
I resized to 800px but the image still looks blurry. Why?
Either the source was smaller than 800px (upscaling blurs), or the image has fine text that resampling softened. For text images, try resizing to exact integer fractions of the original.
What's the difference between resizing and compressing?
Resizing changes pixel count. Compressing encodes those pixels more efficiently. Resize first — it removes more data than compression ever will.
Can I resize 30 images at once?
Yes. Upload up to 30 files and download the results as a ZIP.
Are my files stored after resizing?
No. Files are deleted automatically as soon as the resizing job completes.
Other tools that go well with this one
Compress image · Remove image background · Convert HEIC to JPG
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