Progressive JPEG Checker
Check whether a JPEG uses baseline or progressive encoding and inspect scans, dimensions, subsampling and marker details.
Confirm how a JPEG is encoded
A .jpg extension cannot tell you whether the file uses baseline or progressive JPEG encoding. The reliable answer is stored in the JPEG marker stream, so this tool reads the file structure instead of guessing from the filename.
What the report includes
The checker identifies common baseline and progressive Start-of-Frame markers, counts image scans and reports dimensions, sample precision, component sampling factors, JFIF and EXIF markers, plus a practical chroma-subsampling label when it can be derived.
Why check this?
It is useful when verifying an image-export preset, CMS transformation or CDN output, especially when a delivery requirement specifically calls for baseline or progressive JPEG files.
Local inspection
The JPEG bytes are parsed in your browser. The image is not uploaded or recompressed.
Not a quality score
Progressive encoding does not automatically mean better visual quality or a smaller file. This checker describes the stored encoding structure only.