Understanding KB and MB When Preparing Images for Website Hero Images

Updated March 7, 2026 · 7 min read

Size limits are written in kilobytes and megabytes, and the units trip people up. The hero is usually the largest element on a page and often decides how fast the page feels to load.

Recommended settings for website hero images

SettingStarting point
FormatJPEG (WebP where accepted)
Widthabout 1920 px on the long edge
Quality78
File size300 KB or less

These are practical defaults. If the platform or form you are using publishes its own limits, follow those instead.

Understanding KB and MB When Preparing Images

One megabyte is roughly 1000 kilobytes, and some systems count 1024. If a limit says 100 KB, aim a little under, such as 95 KB, to be safe.

For website hero images, a target of 300 KB is a comfortable default. Our results panel shows the exact size of each compressed file so you can confirm it before uploading.

Step by step with TheCompressJPEG

  1. Open the compress JPEG to 300 KB tool, or the main compressor for custom settings.
  2. Drop in your image. Nothing is uploaded; it is processed in your browser.
  3. Set the maximum width to 1920 and the target size to 300 KB.
  4. Press Compress, check the result and download it.
Ready to try it? Compress your JPEG to 300 KB now. It's free and private.

Quick tips

  • Check the result on a phone, where most people will see it.
  • Use consistent dimensions for a set of related images.
  • Resize before you compress; it improves quality at any file size.
  • Write a size limit slightly below the stated maximum to leave a margin.

FAQ

How do I compress many images for e-learning courses at once?

Drop all of them into the tool together and use Download all to get a single ZIP.

What JPEG quality should I use for e-learning courses?

Quality around 78 keeps photos looking natural while cutting file size substantially.

Will compressing reduce image quality for e-learning courses?

Some detail is removed, but at sensible settings the difference is not visible at normal viewing size.

Wrapping up

For website hero images, the reliable recipe is simple: resize to around 1920 pixels, compress at quality 78 or to a 300 KB target, and check the result before you upload. Keep the original so you can always start again.

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