Compress an image to 300 KB
A full-width article photo that stays sharp and still loads quickly.
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How it works
Add your images
Drag and drop, paste, or pick files. They upload over an encrypted connection.
Pick a quality or a target size
Use the quality slider, or tell it exactly how many KB or MB you need.
Download
Save each file, or grab them all at once as a ZIP.
300 KB is the weight of a good full-width photo on an article page. It holds a picture about 1600 pixels wide with clean detail, which fills a laptop screen without looking soft and arrives fast on an ordinary connection.
The tool searches for the highest JPEG quality that stays at or below 300,000 bytes. A phone original usually needs only a modest quality drop and a reduction in pixels to land there, so the result looks very close to the source at normal viewing size.
At this size the difference between the original and the compressed file is mostly invisible unless you zoom far in. That makes 300 KB a comfortable choice when you want a picture to look professional without carrying a megabyte of weight.
What 300 KB holds
A rough budget for a clean photo is about one bit per pixel, though detailed pictures need more. Three hundred kilobytes is 2.4 million bits, enough for about 1500 pixels square or 1600 by 1000 for a landscape. That is the width most article layouts display at full size.
Hero pictures at the top of a page
The picture at the head of an article is often the largest thing a reader waits for. Keeping it near 300 KB gives a sharp image on a desktop and avoids a long blank space on a phone. If the page also has smaller pictures lower down, they can be far lighter.
Place the hero at the width of your layout, not wider. Extra pixels beyond the display width add weight and no visible sharpness.
High-density screens
Phones and many laptops show twice as many physical pixels as layout points. A picture displayed 800 points wide looks best at 1600 pixels. At 300 KB, a 1600 pixel photo of a landscape or a person looks crisp on such a screen.
Landscapes and busy scenes
Foliage, water ripples and crowds are expensive, because every region differs from its neighbours. If a landscape of this kind comes out soft, reduce the width to 1300 pixels before you compress again. A smaller sharp picture beats a larger blurred one.
Keeping a set consistent
A photo essay with ten pictures at 300 KB weighs three megabytes in all. If that is more than you want, lower the target for the supporting pictures and keep 300 KB for the opening one.
Choosing a size when you are unsure
If you cannot tell whether 300 KB is right, compress at 300 KB and at 500 KB and open both at the size your page shows them. When the two look the same, keep the lighter one. When the larger is visibly cleaner, the page has earned the extra weight.
Trust your eyes on the real page more than any rule of thumb.
Frequent mistakes with large pictures
The biggest mistake is uploading the original and counting on the page to shrink it. The browser still downloads every byte, even when it shows the picture in a small area. A second mistake is double compression, where an already squeezed picture goes through another round.
Start from the original, compress once and publish the result.
Frequently asked questions
Is 300 KB good for a website hero image?
Yes, for a picture up to about 1600 pixels wide. Wider hero pictures may need 500 KB.
Will I see a difference from the original?
Usually not at normal size. Differences appear in fine textures when you zoom in.
Should I choose JPEG or WebP?
WebP is often lighter at the same look. JPEG is the safest choice for sharing with others.
Can I go lower than 300 KB?
Yes. Choose Custom in the Target size menu and enter any number.
Does the picture keep its colours?
Yes. Colours are kept, though very strong compression can band smooth gradients.
How is the 300 KB measured?
In decimal units, with 1 KB as 1000 bytes. The file will be under the limit by either way of counting.