Try a 10 KB target with dimensions locked
This uses the synthetic, 800 × 600 photo-like reference image from Fitabyte Lab. Run it through the same image compressor used on the homepage, with a target of 10 KB (10,240 bytes). Processing happens in your browser.
Download the source WebP image to repeat the test with a different target in Fitabyte Compress.
The WebP source stays WebP in this workflow. This run searches quality settings only and keeps the 800 × 600 dimensions, even if the target cannot be met. It aims at or below the limit rather than padding a file to exactly that size. Browser encoders can produce different byte counts. One synthetic sample does not represent every photograph or screenshot.
Sometimes a marketplace, CMS, print workflow, or design handoff requires the exact same width and height. In that case you cannot use resizing as your first lever. File size must come down through encoding choices instead.
What can change if the dimensions cannot?
- Compression quality in lossy formats such as JPEG and WebP.
- File format itself—for example, PNG to WebP when transparency and destination support allow it.
- Metadata such as embedded thumbnails and camera information.
- Color depth or chroma detail, depending on the encoder.
- Keeping the same dimensions does not preserve every pixel: lossy compression still changes detail. Do not crop and pad a required identity or evidence image merely to reduce its bytes.
There is a hard limit: if an image contains a great deal of fine random detail and you insist on the same dimensions, the encoder eventually has to discard visible detail to keep shrinking the file. No compressor can store unlimited visual information in an arbitrarily small number of bytes.
Format choice can matter more than another quality step
| Image type | Often sensible first choice | Why |
|---|---|---|
| Camera photo | JPEG or WebP | Lossy encoders are efficient with natural tones and gradients |
| UI screenshot | PNG or WebP | Sharp text and flat regions can compress efficiently without JPEG ringing |
| Logo with transparency | PNG or WebP | Transparency is preserved |
| Mixed photo + text | WebP or a carefully tuned JPEG | Balances photographic detail and graphic edges |
A controlled no-resize workflow
- Record the original dimensionsWrite down the width and height so you can verify the result later.
- Keep the original fileEvery lossy test should start from the same source instead of repeatedly recompressing a previous result.
- Test a more efficient formatIf the destination supports WebP, compare it with JPEG or PNG before sacrificing more quality.
- Lower quality graduallyInspect text edges, faces, gradients, and fine texture after each meaningful reduction.
- Verify dimensions and bytesCheck both properties after export. The file can meet the byte limit but still fail the workflow if dimensions changed.
The controlled examples on the Fitabyte Lab show a useful pattern: flat graphics can be extremely compact in PNG or WebP, while photo-like detail requires substantially more bytes. That is why a universal ‘quality 70 equals X KB’ rule does not exist.