Legacy ImageMagick Discussions Archive

JPEG Quality is generally determined by the selection of quantization tables and downsampling.
Is there any way to detect if a jpeg image is downsampled or not and view its quantization tables?

extremis wrote: JPEG Quality is generally determined by the selection of quantization tables and downsampling.

That sounds more like GIF not JPEG. JPEG does not quantize the image to a fewer numebr of colors, but attempts to map a frequency (fourier transform) to generate higher lossy compression.

As for your question. Glenn?