Recommendations to reduce file size?

[Pgr]

Hi all,

I'm new to this forum.

I would like to reduce the disk space taken up by my photos, and I now realize I took many of them in excessive resolution, resulting in file sizes of 3Mb, 6Mb, for each photo. I now use a resolution that results in jpg files ranging from 700Kb to 1300Kb, and I believe this fits my needs perfectly.

I would like to now if anybody can recommend the best generic procedure to turn all my old big files to the smaller ~1Mb sizes. I am a bit confused if what I need is less pixels, less dpi, or whatever (as you can see, I'm not at ease with these concepts!). Also, I know sometimes the fact that some photos are vertical, some horizontal, makes size conversions a bit more tricky, unless NConvert can work with that intelligently.

Can someone please recommend NConvert command-lines to achieve the desired results? Thank you!

[xnview]

First make a bakcup of your files!
You can try

Code: Select all

nconvert -out jpeg -o % -rflag orient -ratio -resize 1280 1024 -q 80 *.jpg

Change 1280 1024 as result size...

[rra]

wouldn't it be better to just scale the number of pixels down to 50% or so,
for both dimensions, giving a 4 times smaller image,
JPEG compression would probably make it some 3 x times smaler file-size I guess,
just the right size PGR wants it to be !!'

René

[Pgr]

Thank you both!

René, can you please give an example Nconvert.exe command-line to do what you suggest? I could try both your suggestions and see which looks better.

I don't know how the resampling algorithms work, but I would think that a 50% reduction would produce better-quality results than some weirder ratio like 63.5%, right?

Thanks.

[rra]

I am not an expert at all using nconvert,
so this is a guess:

nconvert -out jpeg -o % -rtype lanczos -rflag orient -ratio -resize 50% 50% -q 80 *.jpg

As you can see , only the resize parameters are different and the sizing algorithm is set
to Lanczos (this one is generally taken to be the best).


Good luck, and as Pierrre stated:

Make a backup first before you start !!

René

[rra]

I am not an expert at all using nconvert,
so this is a guess:

nconvert -out jpeg -o % -rtype lanczos -rflag orient -ratio -resize 50% 50% -q 80 *.jpg

As you can see , only the resize parameters are different and the sizing algorithm is set
to Lanczos (this one is generally taken to be the best).


Good luck, and as Pierrre stated:

Make a backup first before you start !!

René