How to Reduce Photo File Size – Shrink Photos to a Target KB on Your Phone or Computer

A photo’s file size mostly depends on two things. To make it smaller, lower one or both.

• Dimensions (pixels): halving the width and height makes the file roughly a quarter of the size
• Quality (compression): lower JPG quality makes smaller files, but fine detail blurs and noise appears

Phone photos are often around 4,000 pixels on the long side, far bigger than forms or email need. Shrink them to about 1,000–2,000 pixels first, then lower the quality only if needed; that keeps them looking good.

Size varies a lot with the content: busy detail makes bigger files than sky or plain walls. Treat these as rough guides.

When you attach photos in the Mail app, you may be offered Small, Medium, Large or Actual Size. Small or Medium sends a reduced copy.

To shrink the photo itself, you can make a Shortcut with the “Resize Image” action, but it can’t target a size in KB.

On some phones the gallery app’s editor has a resize option for saving a smaller copy. Whether it exists, and what it’s called, depends on the phone.

In the Windows 11 Photos app, open the photo and choose “Resize image” from the “…” menu to set dimensions and quality. Paint’s Resize also works.

In Mac Preview, use Tools → Adjust Size. File → Export as JPEG shows a quality slider with the resulting file size.

With the methods above you have to save, check the size and try again. This site’s Compress Images lets you type a target such as 200KB and compresses each photo to fit. iPhone HEIC photos work too, and you can do many at once. Your photos are never uploaded.

1. Open Compress Images and choose your photos (several at once is fine)
2. Choose “Set a file size (KB)” and enter the target (e.g. 200KB)
3. Choose the format (JPG if unsure)
4. Tap “Compress images” and download them one by one or as a ZIP

Compressed images don’t keep Exif data such as GPS location, so this is also a way to remove location before posting photos online.

Japanese job sites, school portals and government services often set both a pixel size (such as “at least 600 px wide” or a 3:4 ratio) and a KB limit. Match the dimensions with Resize Images first, then shrink the file with Compress Images. For résumé or My Number card photos, ID Photo Maker crops to the official Japanese sizes.