chizor wrote: hi all,
i am converting a hundred JPEGs from different cameras to thumbnails at fixed resolutions ('60x50!', etc.) and qualities (35, say). thumbnails made from a 4MP camera average 21K and those from 2MP cameras, 7K. since the output files have the same dimensions and compression level, i have not been able to explain this.
If you aren't stripping out the profiles and thumbnails, different cameras could yield different file sizes.
- convert -strip in.jpg out.jpg
in another case, i have found that quality level 100 yields smaller PNGs than some lower levels. given that PNG is a lossless format, what does this parameter impact besides processing time?
In PNG outputs, filesize isn't proportional to quality. Quality is a two-part
value. The 10's digit, which runs from 0 to 9, is the compression
quality. Generally, the higher the better compression and the greater the computer time spent. The one's digit is the "PNG filter type". 0 means
no filtering and 5 means adaptive. For photos, quality 95 usually
yields the best compression, while for drawings quality 90 usualy does
in both cases, which other settings might help me achieve a reliably low filesize?