Image Information
Check Image File Size
File size decides how fast a page loads on a phone connection. Comparing raw weight is only half the picture though: a 900 KB file is reasonable for a 4000 px poster and wasteful for a 600 px thumbnail.
This tool reports the weight of each file alongside its bytes-per-pixel figure, so you can see which images are genuinely inefficient.
Drag images here
Add several images to compare them side by side
How to use this tool
- 1Add the images you want to measure.
- 2Read the file size shown in KB or MB.
- 3Compare the bytes-per-pixel value across your files.
- 4Send the worst offenders to the compress or resize tool.
Reading bytes per pixel
Divide file size in bytes by the number of pixels and you get a format-independent efficiency measure. Well-optimised JPEG photographs usually land between 0.1 and 0.3 bytes per pixel. WebP often sits around 0.08. Anything above 1.0 signals an uncompressed PNG or a photo saved at an unnecessarily high quality.
Sensible budgets for web pages
A practical target is under 200 KB for a content image and under 500 KB for a full-width hero. Total page weight matters too: several 300 KB images add up quickly, and Largest Contentful Paint is usually dominated by the largest one.
What to do about a heavy file
Work in this order: reduce dimensions to what is actually displayed, switch to a modern format, then tune quality. Reversing that order wastes effort, because resizing alone often removes most of the weight.
Frequently Asked Questions
Why is KB different from KiB?
Sizes here use 1 KB = 1024 bytes, matching what most operating systems report. Some tools use 1000 bytes, which produces slightly larger numbers.
Does file size affect SEO?
Indirectly. Heavy images slow page loading, and loading speed is part of the page experience signals search engines use.
Why do two images of the same dimensions differ so much in size?
Content complexity. Noise, texture and gradients compress poorly, while flat colour compresses extremely well.
Is anything uploaded?
No. File sizes are read from the local file object in your browser.