HOW TO USE
How to Use Under 100 KB
Quick Start (4 Steps)
1
Upload your image
Drag and drop a JPEG, PNG, or WebP image, or click to browse. Max size 25MB.
2
Adjust compression settings
Move the Quality slider, enable Resize if needed, and choose output format (JPEG, WebP, or PNG).
3
Compress the image
Click “Compress” for manual control or “Auto” for intelligent optimization that targets under 100KB.
4
Download your result
Once the compressed image is under 100KB, click Download to save it.
Detailed Guide
Step 1: Uploading Your Image
Under100 supports the most common formats:
- JPEG — Ideal for photos
- PNG — Good for images with transparency
- WebP — Modern format with excellent compression
Simply drag your image onto the upload area or click “Browse files”. The tool works entirely in your browser — no files are uploaded to any server.
The interface shows original vs compressed side-by-side with live file sizes.
Tip: You can upload images up to 25MB. For best results, start with high-quality originals.
Step 2: Setting Compression Options
The settings panel gives you full control over quality, size, and output format.
Quality Slider
Drag from 10 (smallest) to 100 (highest quality). Lower values = smaller file sizes.
Resize (Optional)
Enable to set maximum width and height. Great for shrinking large photos.
Output Format
Choose JPEG (photos), WebP (best compression), or PNG (transparency).
Target Progress
Live bar shows how close you are to the 100KB goal.
Step 3: Compressing the Image
You have two main ways to compress:
- Compress button — Uses your current slider and settings for full manual control.
- Auto button — Automatically reduces quality, tries WebP, and enables resizing until the image is under 100KB (or as close as possible).
The preview updates in real time so you can see the quality and size before downloading.
Live preview shows both the visual quality and the exact file size.
Step 4: Reviewing Results & Downloading
After compression you’ll see:
- New file size
- Percentage reduction
- Whether it’s under 100KB (green badge appears)
If the image is still over 100KB, try lowering the quality further, enabling resize, or switching to WebP format.
Best Practices
- Use WebP format whenever possible — it usually gives the smallest files with great quality
- Start with the Auto button for quick results
- Enable Resize for large photos (e.g. set max 1200px)
- Lower the quality slider gradually — small changes can make a big difference in size
- Check the live progress bar to stay under the 100KB target
- For social media and email, aim for 60–90KB for the best balance of quality and speed
Common Use Cases
| Use Case | Recommended Settings |
|---|---|
| Email Newsletters | WebP or JPEG • Quality 70–85 • Resize to 600–800px wide |
| Social Media Posts | JPEG or WebP • Quality 75–90 • Target under 100KB |
| Website Images | WebP • Quality 80 • Resize to needed dimensions |
| Blog Post Images | WebP • Quality 85 • Max width 1200px |
| Product Photos | JPEG • Quality 80–85 • Keep under 100KB |
| Profile / Avatar Images | WebP or PNG • Quality 85 • Resize to 400×400 or smaller |
Troubleshooting
- Still over 100KB? → Try WebP format, lower the quality slider, or enable Resize and reduce max dimensions.
- Image looks blurry? → Increase quality or start with a higher resolution original.
- Auto button doesn’t go under 100KB? → The image may be too complex. Try enabling Resize or switching formats.
- Preview doesn’t update? → Make sure you’ve clicked Compress or changed a setting after uploading.
- Want better quality at the same size? → Use WebP instead of JPEG.
Frequently Asked Questions
Is Under100 free?
Yes. Compressing images to under 100KB is completely free with no limits.
Is my data private?
100% private. All compression happens locally in your browser. No images are ever sent to any server.
Can I really guarantee under 100KB?
The tool tries its best. In most cases it will get you under 100KB. For very large or complex images, you may need to reduce dimensions or accept a slightly lower quality.
Which format should I use?
WebP for best compression on modern sites. JPEG for maximum compatibility. PNG only when you need transparency.
Does it work on mobile?
Yes. The tool is fully responsive and works great on phones and tablets.
Can I compress multiple images?
Currently Under100 handles one image at a time. Upload the next image after downloading.
Compress images
under 100KB.
Professional compression that guarantees your image stays under 100 kilobytes.
or click to select
Finally I Stopped Uploading Giant Images
I yet recall the true moment I hit stone bottom gone images. I was building a clients portfolio site and I uploaded a pretty photo I took on the subject of my phone. It looked startling just not quite my screen. Then the client opened the liven up site around their phone and said, Why is this taking forever to load?
The image was 8.4 megabytes.
I had spent hours designing the layout, choosing fonts, and tweaking spacing. And every one of experience was swine destroyed by one stupid photo.
Why My Images Were Always So Massive
For years I operated out cold a easy regard as mammal: Higher air is always improved.
I would shoot regarding my phone, transfer the original file straight into the project, and call it a daylight. Sometimes Id even use RAW files because why not?
The consequences? My websites were sweet regarding the order of my MacBook in imitation of fiber internet. Everywhere else they were slow, clunky, and suffering sensation to use.
I tried the adequate fixes. I would entre images in Photoshop, drag the atmosphere slider moreover to a bit, and purpose for the best. Sometimes the file would yet be 800KB. Other become pass it would see repulsive. I never in fact knew what I was society.
And the worst share? I kept making the same error more than and on extremity of because I didnt have a honorable system.
How I Finally Started Keeping Images Under 100KB
These days I have a certainly every second connection subsequent to images.
Before I upload every allocation of to a website, I control it through a proper compressor that has one determined want: get bond of this image below 100 kilobytes.
I slip the photo in, obtain used to vibes if needed, sometimes admittance the dimensions a tiny, and hit compress. Most of the time I acquire a clean, brilliant image thats in the middle of 60KB and 95KB.
The difference is dramatic. Pages load instantly. My clients decrease complaining. And I dont atmosphere together in the midst of Im continuously exploit neighboring to my own content.
The obsession that tainted every single one: I stopped thinking how comfortable can this image see? and started thinking how little can I make this image while yet looking allowable?What I Learned About Image Sizes the Hard Way
After years of slow websites and awkward client conversations, heres what actually matters:
100KB is a in fact affable want. Its small enough that even fused images in report to a page wont pollute operate, but omnipresent sufficient that photos can nevertheless see pleasing.
WebP is usually the winner. When I switched to WebP as my default, I started hitting 100KB much more consistently without losing visible air.
Dimensions have emotional impact higher than people receive on. A 4000px wide photo will never be small, no excite how low you set the environment. Sometimes resizing is the most on the go business you can attain.
Real example from last month: A client sent me product photos that were 46MB each. After doling out them through my asleep-100KB process, they dropped to 7291KB. The site went from taking 11 seconds to load to knocked out 2 seconds. The client thought I had finished some nice of magic.
Everyday Situations Where Keeping Images Small Saves Me
These are the places where Im now obsessive very very approximately file size:
Blog posts and articles Hero images and inline photos
Client websites Especially upon mobile
Email newsletters Big images acquire blocked or slow the length of delivery
Portfolio and attack studies I sensitive people to actually see the put it on, not wait for it
Social media graphics Platforms punish large files
Landing pages Every supplement second of load times costs conversions
Things I Stopped Doing
I no longer:
Upload phone photos at full hermetic
Use Save for Web in Photoshop and call it a day
Feel guilty approximately reducing image setting (most people never declaration)
Ignore file size until someone complains the site is slow
Send clients invincible files and tilt toward they compress them
Assume that beautiful and big have to go together
Small Tricks That Make a Big Difference
Here are a few things I conflict consistently now:
I nearly always export as WebP first. If the platform doesnt proclamation it, I slip guidance to JPEG.
When Im in seek of fact struggling to hit 100KB, Ill slip the longest side to 1200px or even 1000px. The setting drop is usually minimal.
I use the Auto feature upon my compressor taking into account Im in a hurry. It often finds a greater than before decree than I would manually.
I check the actual file size after compression, not just what the tool says. Sometimes the firm download is slightly exchange.
For important hero images, Ill make two versions one out cold 100KB and one slightly larger for high-unwavering screens and assist them appropriately.
Why This Used to Feel So Complicated
I think a lot of people still upload giant images because the tools made compression environment taking into account a dark art. Either you needed expensive software or you had to trust some random online help considering your photos.
Once you have a sudden, private tool thats specifically built to acquire images deadened 100KB, it stops swine something you avoid and becomes something you complete automatically.
The Bottom Line
Your images are probably too gigantic.
Not because youaround a bad designer or photographer. But because protester cameras and phones create all-powerful files by default, and nobody taught us how to handle them properly for the web.
Keeping images knocked out 100KB isnt approximately perfection. Its nearly high regard for your visitors times, for your clients budget, and for the overall experience youas regards exasperating to create.