What 150 KB looks like
At 150 KB the test photo kept its full 2000 x 1333 pixels and came out at 149 KB with JPEG quality 68, which looks clean at normal viewing size. The screenshot and the illustration fit at quality 37, the ceiling the search uses, at 145 KB and 115 KB.
| Test image | Original | Result | JPEG quality | Pixels | Time |
|---|---|---|---|---|---|
| Photo | 694 KB | 149 KB | 68 | 2000 x 1333 | 3.4 s |
| 12 MP photo | 1.81 MB | 145 KB | 37 | 3040 x 2027 (from 4000 x 2667) | 11.0 s |
| Screenshot | 46 KB | 115 KB | 95 | 1600 x 900 | 452 ms |
| Illustration | 94 KB | 81 KB | 95 | 1200 x 1200 | 413 ms |
Test images are synthetic files made by this project: a 2000 x 1333 landscape photo, a 1600 x 900 interface screenshot and a 1200 x 1200 transparent illustration. The 12 MP photo is the same photo scaled up to 4000 x 2667, the size a phone camera saves. Quality is lowered first and the image is only scaled down when quality alone cannot reach the target. A JPEG that is already under the target is left as it is. Timings: one thread of WebAssembly on Node v22.23.4, Intel(R) Xeon(R) Processor @ 2.10GHz, 2 cores, measured 2026-10-31. Other devices will differ.
A budget for hero and featured images
This is a useful ceiling for the large image at the top of an article. The built-in recipe Blog featured: 1200x675 WebP under 150 KB, metadata removed, does the whole job in one step: it crops to the shape, scales to 1200 x 675, fits the size and strips metadata. Pick it from the Recipe list in Advanced settings on any page.
In the batch test on the bulk converter page, five different files all landed under 150 KB at 1200 x 675 through that recipe. A 3.75 MB PNG photo came out at 146 KB.
JPEG or WebP at this size
This page defaults to JPEG for compatibility. If your site or CMS accepts WebP, change the output format and keep the 150 KB target. You get a file in the same range with a little more detail, or the same detail in fewer bytes.
Alt text and file names
Open Advanced settings and look under File names to rename outputs with patterns such as {name}-{width}x{height}. On the bulk page you can also add alt text for each image and export everything as a CSV.
A repeatable blog image routine
- Open Advanced settings and choose the Blog featured recipe from the Recipe list.
- Drop the images, or a whole folder, onto the page.
- Check one or two results in the compare view.
- Write alt text for each image under Details, then download the files as a ZIP and the list as a CSV.
- Upload the WebP files to your CMS and paste the alt text from the CSV.
The recipe removes metadata, so the files carry no camera details or location. Names follow {name}-{width}x{height}, so a file called harbour-at-dusk-1200x675.webp tells you its size at a glance. Free use covers 10 images a day.
Why two photos land at different qualities
Foliage, fabric and gravel are hard to compress, while a smooth sky or a studio backdrop is easy. Two photos with the same pixel size can therefore settle at very different qualities under the same 150 KB. The result line shows the quality for each, and a low number on a busy photo is a sign to try a smaller pixel size.
Questions
Is 150 KB too big for the web?
For one large image it is reasonable. For a page full of photos, aim lower, such as <a href="/compress-image-to-100kb/">100 KB</a> or <a href="/compress-image-to-50kb/">50 KB</a> each.
What does "never enlarges" mean here?
If the picture is smaller than your target dimensions, the tool keeps its size. It does not stretch it.
Can I save my own recipe?
Yes. Set things up, then choose Save these settings as a recipe. It is stored in your browser only.
Is this the same engine as the other pages?
Yes. Every page uses the same code and differs only in its defaults.