A budget that rarely forces a visible compromise
At twelve hundred pixels wide, a typical photograph reaches this figure at a quality level around the mid seventies, which is comfortably above where artefacts become noticeable. Drag the comparison slider on your result and the honest answer is usually that you cannot tell.
That headroom means you can prioritise something else. Keep more width for a landscape that will be viewed large, or push the quality higher on a portrait and accept a narrower frame.
Choosing the format at this size
WebP is the sensible default and is what this page selects. It reaches a hundred kilobytes with visibly more detail than JPEG at the same figure, and every current browser displays it. Use JPEG instead when the destination is an older system, an email client you do not control, or an upload form that names its accepted formats.
Where a hundred kilobytes is the right call
For a page with a single large illustration, this is close to ideal — fast on a mobile connection without looking cheap. For a gallery of thirty thumbnails it is far too generous, since thirty of them is three megabytes before anything else on the page has loaded. Match the budget to how many images the reader will actually receive.
Questions
- Is 100KB good enough for a website header image?
- For most designs, yes. A header displayed at around twelve hundred pixels wide looks clean at this size in WebP. If the header spans a very wide screen and contains fine detail such as text over a photograph, allow two hundred kilobytes and compare the two results before deciding.
- Why is my compressed file smaller than 100KB when I asked for 100KB?
- The target is a ceiling rather than a goal. The tool searches for the highest quality that still fits underneath it, and if your image is simple it may fit at maximum quality with room left over. A result well below target means the picture was inexpensive to encode, which is good news.
- Can I compress several images to 100KB at once?
- Yes. Drop them together and each one is searched for its own quality level against the same target, since a flat graphic and a detailed photograph need very different settings to land at the same size. The free plan handles five at a time.
- Does a hundred kilobytes mean the same thing for a screenshot as for a photograph?
- Not remotely. A screenshot is mostly flat colour and hard edges, which lossless PNG stores cheaply and exactly, so a screenshot often reaches this budget at full resolution with nothing thrown away. A photograph must spend the entire allowance describing continuous variation across every pixel. Judge the two by different standards: a screenshot at this size should look untouched, whereas a photograph is making a genuine trade.